Blenderart Magazine - 03 - Rendering Special

Us ing Y afray in profe s s ional e nvironm e nt. Le arn h ow to us e S unfl ow re nde ring s y s te m . Y afray caus tics e xpl aine d. Le arn m ore about Y afray G I. D PI de m y s tifie d Re nde ring optim iz ation.

CO NTENTS

EDITO R Gaurav Naw ani M ANAGING EDITO R Sandra Gil be rt

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W RITERS Sandra Gil be rt Cl aas Eick e K uh ne n Danie lLaBarge Ch ris toph e r K ul l a Z s ol tSte fan DESIGN & GRAPH ICS Gaurav Naw ani W EBSITE DESIGN Nam Ph am CO PYRIGH T© ‘Bl e nde rartM agaz ine ’, ‘bl e nde rart’ and bl e nde rartl ogo are copyrigh tGaurav Naw ani. ‘As k Bl e ntuu’ and ‘bl e ntuu l ogo’ are copyrigh tSandra Gil be rt. Al lproducts and com pany nam e s fe ature d in th e publ ication are trade m ark or re gis te re d trade m ark ofth e ir re s pe ctive ow ne rs . w w w .bl e nde rart.org

ED ITO RIA L

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You’ve s tudie d al lth e tutorial s , you buil tth e pe rfe ctm ode l , adde d th e pe rfe ctm ate rial , now its tim e to re nde r your w ork ofart. You h itth e big “Re nde r” button, w aitfor w h ats e e m s l ik e fore ve r . . . and w h e n itfinal l y finis h e s . . . w e l lto be h one s t, th e e nd re s ul tl ook s noth ing l ik e w h atyou h ad im agine d. W h atw e ntw rong? M os tl ik e l y, q uite a bitw e ntw rong. Re nde ring is th e re s ul tofe ve ryth ing th atcam e be fore and as s uch th e re are a l otoffactors th atcan m ak e or bre ak you finalim age . Is your l igh ting jus t righ t, are your s e ttings corre ct, did you accountfor al lth e s pe ciale ffe cts you adde d. Eve n ifyou ge tal lth e above righ t, you m igh ts pe nd h ours or days w aiting for th e finalre nde r to finis h , onl y to dis cove r you ne e d to tw e ak s om e th ing jus ta l ittl e. Wel com e to Is s ue #3 “Re nde ring”. In th is is s ue w e w il lbe cove ring s om e ofth e is s ue s th at affe ctyour finalre nde r, bringing cl arity and be tte r unde rs tanding to ach ie ve th e be s tre nde r pos s ibl e. In addition to l ook ing into th ings th atcan im prove your re nde rs , w e w il lal sol ook atw ays to de cre as e your re nde r tim e s as w e l las tak e a l ook ats om e ofth e Re nde r e ngine s avail abl e for Bl e nde r. O fw h ich q uite a fe w h ave be e n de ve l ope d re ce ntl y and w arranta l ook s e e . W e al s o h ave 3 s e parate articl e s on h ow to us e Yafray, w ith e ach s h ow ing a diffe re ntte ch niq ue and m e th od ofus e . Ch e e rs ! Sandra s andra@ bl e nde rart.org

Bl e ntuu s ay s

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Re nde ring is an ofte n m is unde rs tood proce s s and until w e ge tth e “m ak e re nde r be autiful button” ;) code d, w e h ave to do it th e h ard w ay. And th atw oul d be by unde rs tanding w h atgoe s into a re nde r and w h ataffe cts th e re nde ring proce s s . Th e s h ortans w e r is th atEVERYTH ING affe cts th e re nde ring proce s s . Th atw oul d incl ude m ate rial s,l igh ting, s pe ciale ffe cts and th e s ce ne its e l f. And w h il e dis cus s ing re nde ring coul d fil la w h ol e book , for th is articl e w e are going to tak e a l ook attips and trick s th atcan incre as e or de cre as e your re nde r tim e s and q ual ity. W h e n itcom e s to re nde ring, s om e th ings jus ttak e l onge r. Ifyou jus th ave to h ave th atce rtain e ffe ct, by al lm e ans go for it, but e xpe ctto w aita w h il e for your re nde r to com pl e te . H e re is a l is t ofs om e th ings th atare l iabl e to incre as e your re nde r tim e : Raytracing, Am bie ntO ccl us ion Ligh ting Se tups H e avy us e ofparticl es Extre m e l y de tail e d s ce ne s O n th e oth e r h and, CG artis ful loftrick s and w ork -a rounds to l ow e r re nde r tim e s , s uch as th e us e ofth e fak e GI dom e . Long us e d in bl e nde r be fore AO w as code d into bl e nde r. It is s im pl e to s e tup, e as y to adjus tand notas com putation h e avy as th e AO option.

To s e tone up is e as y: Add>M e s h >Icos ph e re , s ubdivis ion 2 De l e te th e bottom h al fofth e Icos ph e re Add a s potl igh t, and pare ntitto th e Icos ph e re H itF7, (O bje ctSe ttings w indow ) W ith th e Icos ph e re s e l e cte d, pre s s th e dupl ive rtbutton. Se l e ctth e s potl igh tand adjus tth e Ene rgy w ay dow n (around .01) Adjus tth e re s tofyour s e ttings as ne e de d to ge tth e am ountof l igh tand s h adow you are l ook ing for. O th e r th ings th atcan l ow e r re nde r tim e s : Ge ne ral l y us e z -buffe r l am ps ove r raytrace d one s . Se tth e s am pl e s and s h adow buffe r as l ow as pos s ibl e for th e q ual ity you l ook ing for. Sim il arl y, turn th e s am pl e s dow n on e ve ryth ing as l ow as you can ge taw ay w ith th atpe opl e probabl y w il lnotnotice (l igh ts , s ubs urf, rayde pth , e tc.).Re nde r in pas s e s w h e n pos s ibl e , you can re -com pos ite th e pas s e s in GIM P or Ph otos h op, notonl y w il l itl ow e r re nde r tim e s , you w il lh ave m ore controlove r h ow e ach l aye r goe s toge th e r w ith th e oth e rs . O nl y m ode lth os e de tail s th atare ne e de d, UVm apping and prope r us e ofte xture s can s ave on your pol ygon count. W h e n it is al ls aid and done , us e onl y th os e options and te ch niq ue s th at you actual l y ne e d to m ak e your im age or anim ation l ook good. Ifyou can ch e ator fak e it, th e n do s o, itw il ls ave on your re nde r tim e s . If you jus th ave to us e it, th e n be pre pare d for th e w ait. W h il e w aiting I s ugge s tre l axing w ith a nice cup ofcoffe e and a good book .

NEW S Fl as h

Th e bigge s te ve ntin th e Bl e nde r w orl d is jus taround th e corne r. Proje ctO range is ne ar com pl e tion and th e pre m ie r of “El e ph ants Dre am ” h as be e n s ch e dul ed for M arch 24, 2006. Cine m a K e te l h uis , a wel lk now n cine m a for docum e ntarie s and art-h ous e m ovie s in Am s te rdam , h as be e n ch os e n as th e l ocation for th e l ong aw aite d pre m ie r. Th e cine m a ope ns at17:30 and th e s h ow ing w il ls tartat18:00. In addition to th e s cre e ning of“El e ph ants Dre am ”, th e re w il lal s o be a pre vie w ofth e “M ak ing of” docum e ntary. Ifyou m is s th e firs t s h ow ing, th e re w il lbe anoth e r at18:45. Afte r th e pre m ie r, th e re is a ce l e bration pl anne d atone ofth e h ippe s tnigh tcl ubs , ironical l y nam e d “Bl e nde r”. W h il e th e pre m ie r is fre e ofch arge , th e re is an e ntrance fe e to th e “afte r party”. Saturday 25 and Sunday 26 M arch , th e Proje ctO range te am w il lbe on h and al l

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day in M onte vide o (K e iz e rs grach t264, Am s te rdam ) for furth e r vie w ing and dis cus s ion ofth e proje ct. For m ore inform ation on th e pre m ie r and th e fol l ow ing pre s e ntations ofth e m ovie ch e ck h ttp://orange .bl e nde r.org/. Bl e nde r h as be com e an e ve r ch anging program , w ith ne w fe ature s cons tantl y be e n w ritte n and re vis e d for be tte r and cl e ane r functional ity. O ve r th e l as ttw o m onth s , m ajor coding e fforth as be e n focus e d into th e “Noodl e s ” s ys te m (node e ditor) and th e re nde r e ngine . Th e Noodl e s s ys te m al l ow s for th e cre ation of h igh l y advance d m ate rial s and com pos iting e ffe cts . Th e re nde r e ngine is be ing s tre am l ine d and m odifie d to w ork cl e ane r and m ore e fficie ntl y, al l ow ing for fas te r and m ore e rror fre e re nde ring. To ch e ck a te s tbuil d w ith th e s e ne w fe ature s , drop by th e te s tbuil d forum at w w w .bl e nde r.org. Since th is is s ue is focus ing on re nde ring, th is is a good tim e to e xpl ore al lth e re nde r e ngine s avail abl e for us e w ith

bl e nde r. In addition to YafRay, PO V-Ray, M e gaPO V, th e re are now e xports cripts avail abl e for th e fol l ow ing ne w e ngine s : K e rk yth e a Site : h ttp://w w w .s oftl ab.e ce .ntua.gr/~ jpanta/Gra ph ics /K e rk yth e a/ Sunfl ow Site : h ttp://s unfl ow .s ource forge .ne t/ Indigo Site : h ttp://h om e page s .paradis e .ne t.nz /nick am y /indigo.h tm l 3De l igh t Site : h ttp://w w w .3de l igh t.com / M e tropol igh t Site : h ttp://w w w .3dvirtual igh t.com /m l t/

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th e conce pts and troubl e s h ootpos s ibl e probl ems.

Introduction A good im age is w orth a th ous and w ords in Indus trialde s ign indus try. Bl e nde r h as be com e an e s s e ntialtoolfor m y w ork , be caus e ital l ow s m e to vis ual iz e an ide a w ith gre ate r fl e xibil ity th an any h and s k e tch , and th us vis ual l y com m unicate s m y de s ign and conce pt. W h il e Bl e nde r is notm ade for CAD/CAM and l ack s m any fe ature s th os e pack age s fre q ue ntl y incl ude , itis s til lpos s ibl e to us e itnotonl y for productre nde ring, but al s o, to s om e de gre e , th e w h ol e de s ign proce s s . Part1: M ode l ing As an obje ctde s igne r w ith a re ce ntfocus on m e tals m ith ing, Bl e nde r provide s m e w ith al l th e ne ce s s ary m ode l ing tool s to de s ign, e xpl ore , and cons tructm y obje cts . Th e Pol ygon tool s , toge th e r w ith Subdivide d Surface s , al l ow m e to m ode lal ls h ape s , w h ich I w oul dl ate r be abl e to cons tructin m e talw ith m y h ands . In s il ve r s m ith ing, m os ts h ape s are cons tructe d outofs h e e ts , w ire , and tubing. El e m e nts can be be ntby h and or forge d ove r s h ape s and th e n s ol de re d toge th e r. Th is m e ans th atI m ainl y de alw ith ge om e tric

prim itive s h ape s . And th os e are ve ry e as y to m ode lin bl e nde r. Th e re ce ntaddition to cal cul ate th e l e ngth and angl e e dge s furth e rs m y abil ity to account for corre ctm e as ure m e nts and dim e ns ions . Th is is one ofth e m os tim portantadvantage s 3D m ode l ing can provide you, be caus e you h ave th e pos s ibil ity to w ork in corre ct proportions and dim e ns ions . Sm al lch ange s w ith in th e de s ign or a ch ange ofth e pointof vie w can be ach ie ve d w ith a fe w m ous e cl ick s and do notre q uire th e h and s k e tch to be com pl e te l y re draw n. (Scre e ns h ot: M e as ure m e nts )

In addition, notonl y doe s Bl e nde r al l ow to m ode lm e ch anicale l e m e nts , ital s o m ak e s it pos s ibl e to anim ate th e m , al l ow ing m e to proof

In O rth ograph ic Vie w , s cre e ns h ots can be tak e n ofth e w ire fram e and com pos e d toge th e r. Afte r printing on pape r th e y can be cutoutand gl ue d onto th e s il ve r s h e e t, to aid as guide s for th e s h ape s I s aw in th e m e tal . W ork ing in l aye rs aids a l otin th is proce s s be caus e e l e m e nts can be dis tribute d th rough th e m and th e n s e l e ctive l y s h ow n to cre ate cl e ar and us e fuls cre e ns h ots . (Scre e ns h ots : O utl ine s )

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Profe s s ionalD igitalStudio Re nde ring w ith H D RI IBLand G I

Part2: Te xturing Th e curre ntve rs ion ofBl e nde r and Yafray s upportm os tte xture s and s urface l igh t m ode l s th atan artis tne e ds to cre ate pre conce ive d m ate rials im ul ations . H ow e ve r s pe cific m ate rial s l ik e brus h e d m e talor trans l uce ntm ate rial s are s til le ith e r notye t pos s ibl e or onl y pos s ibl e w ith additionaltrick s and tim e . Spe cifical l y in m y cas e , I am unabl e to acq uire th os e anis otropic re fl e ctions and s pe cul ar h igh l igh ts , w h ich are re q uire d to accurate l y s im ul ate th e fine -brus h e d s urface s w ith w h ich I w ork . Butto s om e de gre e th is fe e lcan be ach ie ve d by us ing a proce dural nois e m ap or a painte d bum p m ap. Th e probl e m is th atyou can onl y re ach a ce rtain am ountofde tailbe fore you w il lrun into m oir patte rns during re nde rings . H ow e ve r e ve n a s om e w h atcoars e bum p m ap al re ady provide s e nough de tailto s im ul ate a brus h e d s urface . Th e te xture ne e ds to be s tre tch e d al ong one axis and ne e ds to h ave th e righ t s cal e . (Scre e ns h ots : Prode cural te xture 1+ Te xture 2)

Al s o, a s m al lcol or tintfor th e re fl e ctions and h igh l igh ts w il lre duce th e s te ril e l ook of raytrace d re fl e ctions a l otand atth e s am e tim e give th e re nde ring a fe e l ing w h ich I am us e d to ge tting from us ing re als tudio l am ps . Th os e l am ps do notproduce w h ite l igh t. Th e l igh tis al w ays a bitye l l ow . Itw as al so im portantto give th e ground pl ane a diffe re nt col or th an pl ain bl ack . Th os e h ue val ue s w e re ve ry m inim al l y diffe re ntfrom pure bl ack but e nough to cre ate a naturall ook . Part3: Re nde ring For m y re nde rings , I h ave th e e xpe ctation th at th e finalre s ul ts h oul d be as re al is tic as pos s ibl e . I us e Yafray as th e prim ary re nde r e ngine , be caus e its uppl ie s m e w ith H DRi l igh ting, Gl obalIl l um ination, Col or Bl e e ding, Caus tics , and true De pth of Fie l d. Spe cifical l y for m y type of w ork re nde rings , w h ich m im ic

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th e ae s th e tics ofs tudio s h ots , th e s e fe ature s are e s s e ntialin com m unicating w h atm y w ork is about. H DRi IBLcan provide th e prope r naturall igh tdiffus ion and col oriz ation, w h ich are s ough tin obje ct s tudio ph otograph y. In m y cas e , I us e an H DRi fil e w h ich contains onl y tw o l igh t are as , s im ul ating th e diffus e d l igh tw al l s. Th is w il lproduce e xtre m e l y s ofts h adow s and re duce th e am ountofburning h igh l igh ts . Th is l igh tprobe s uppl ie s th e de s ire d am ountofl igh tfrom th e prope r dire ction in th e s ce ne , w h il e el im inating any unw ante d re fl e ctions (or h ots pots ) on th e w ork . Th e H DRi l igh tm ap (be l ow ) w il lfurth e rm ore not onl y il l um inate th e frontvie w ofth e obje ct, but al s o e m ite nough l ow k e y l igh tto il l um inate th e m e talw ork from al loth e r dire ctions . Th is el im inate s any ne e d for s m al ll igh tarrays to brigh te n up s pe cific are as , l ik e th e traditional th re e -k e y l igh ts e tup.

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Furth e rm ore , th e GI option notonl y accounts for a prope r s h adow cal cul ation and il l um ination ofth e w h ol e ge om e try, but al so incre as e s th e re al is m ofth e re nde ring w ith cal cul ating col or bl e e ding and caus tics . M any productre nde rings l ack th os e fine de tail s ne e de d. O fte n, itis th os e fine de tail s th atw il l h ave a s ignificantim pacton th e vie w e r w ith th e re al is m fe l tw h il e vie w ing th e re nde rings . Butjus ts e l e cting an H DRi l igh tm ap is not al w ays e ve ryth ing you can do. In m y s ituation, I onl y ge tl igh tfrom one s ide . Be caus e of ae s th e tic re as ons , you w antto e l im inate or l igh te n th e dark are as s o as to incre as e th e ove ral ldynam ic range ofth e re nde ring. To brigh te n up s h adow s and dark are as , w h ite l igh tre fl e ctors are us e d in re all ife ph otograph y. Sam e trick appl ie s to digital re nde ring w ith GI.

Re nde ring: ch rom e bal l _ te s t

Sce ne : s e tup3D Anoth e r ve ry im portanttoolfor products h ots is th e De pth ofFie l d. Th is fe ature s is ve ry us e fulin attracting atte ntion to th e s pe cific el e m e nts ofm y w ork , w h il e oth e r e l e m e nts are bl urre d. Yafray s upports true DoF, w h ich w ith h igh e r s am pl e val ue s w il lproduce ve ry s m ooth re s ul ts . Th e re nde r tim e w il lobvious l y incre as e w ith th e am ountofs am pl e s , butth e e nd re s ul tis m ore th an w orth it. Th e DoF s e ttings can be acce s s e d from w ith in Bl e nde r. An ape rture val ue of0.1 to 0.5 is s ufficie nt. To gain a s m ooth DoF re nde ring, in th e re nde r s e ttings you ne e d to dis abl e auto AA. De pe nding on th e s ce ne you h ave to adjus t th e AA s e ttings , in m y s ce ne I us e d 15 * 15 for AA Pas s e s and AA Sam pl es.

Th e fol l ow ing tw o s cre e ns h ots cl e arl y s h ow th e diffe re nce . Th e GI cal cul ate s notonl y th e l igh tcom ing from th e H DRi m ap, butal so cal cul ate s th e l igh tbounce d back by th e l igh t re fl e ctors and th is brigh te ning up ofth e s h adow s on th e cigare tte s al s o adds m ore de tailto th e m e talre fl e ctions . As you al s o can s e e , I us e a ch rom e bal lto find outw h e re th e l igh tis com ing from , th atinform ation e nabl e m e to pos ition th e m e talw ork corre ctl y in th e s ce ne . Sce ne : Topvie w

Scre e ns h ots ne xtpage : AA Se ttings + DoF_ s e tup

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re s ul t. Dirty one , Bl e nde r inte rnal : Th e re fl e ction can be diffus e d w ith a fine nois e m ap in th e norm alch anne l . Th is is a q uick w ay to cre ate bl urre d re fl e ctions , th ough th e y are notph ys ical l y corre ct. In th is cas e , be caus e th e re fl e ction s h oul d notge ttoo m uch atte ntion, th is probl e m is notofany m ajor s ignificance .

Re nde ring: true _ bl urre d_ re fl _ nobum p Yafray doe s nots h ow s bl urre d re fl e ctions in oth e r re fl e ctions , w h ich m igh tbe in s om e s ituations a l im itation. For je w e l ry re nde rings , I pre fe r a te xture d ground. O ne ofm y re ce ntw ork is s h oton a bl ack , s e m i-re fl e ctive s urface , w h ich h as a fine grain te xture . A com m on m is tak e m ade in s im ul ating th is e ffe ctis to s e l e cta too s trong re fl e ctive val ue . Th e re fl e ction on th e picture ground s h oul d onl y be s l igh tl y vis ibl e , s o it accom panie s th e m ain obje ctand pre ve nts from appe aring as a fl oating obje ct. Additional l y, too s h arp re fl e ctions w il lonl y dis tractth e vie w e r and s te alatte ntion aw ay from th e w ork . Th e re are tw o pos s ibl e w ays to ach ie ve th is

Cl e an one , Yafray Yafray its e l fs upports th e bas ic fe ature s of bl urre d re fl e ctions . Unfortunate l y, th is fe ature is notacce s s ibl e from w ith in Bl e nde r inte rface . You ne e d to m anual l y e ditth e e xporte d XM L fil e and th e n re nde r from Yafray. Furth e rm ore

To e xportth e s ce ne into an XM Lfil e , al lyou ne e d to do is to e nabl e th e XM Le xport, s tart to re nde r, and s top Yafray th e m om e ntitis finis h e d w ith l oading th e s ce ne and s tarting to re nde r(ch e ck th e te rm inalw indow for th is during re nde ring). O pe n th e XM Lfil e in any te xte ditor and e nte r th e fol l ow ing s h ade r inform ation into your XM Lfil e.

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Profe s s ionalD igitalStudio Re nde ring w ith H D RI IBLand G I

Firs tincl ude th e cone trace s h ade r atth e be ginning ofyour xm ldocum e ntafte r th e <s ce ne > tag. <shader type="conetrace" name="env" reflect="on" angle="10" samples="16" >

Th e s am pl e val ue w il lde fine h ow fine th e bl urre d re fl e ction is . H igh e r val ue s above 10 produce th e de s ire d s m ooth re s ul tin m y s ce ne . Butth is al s o de pe nds on th e dis tance be tw e e n your cam e ra and th e obje ct. In cl os e -ups h igh e r val ue s are ne e de d. W h e n you us e th e cone trace s h ade r, you can dis abl e th e re fl e ction prope rtie s ins ide bl e nde r. In th e ne xts te p you add "<e nvironm e nt val ue ="e nv" />" ins ide th e m ate rials h ade r bl ock you w antto be re fl e ctive . Se e code box on righ t. Afte r th is s te p, and s aving th e fil e , al lyou ne e d to do is to l e tYafray re nde r th e xm lfil e . For m y conve nie nce I cre ate d a s h ortcutto Yafray.e xe . I onl y drag and drop th e xm lfil e on th e s h ortcuticon and th e re nde r proce s s s tarts autom atical l y.

<shader type="blendershader" name="MAMaterial.002" > <specular_color r="1.000000" g="1.000000" b="1.000000" /> <mirror_color r="1.000000" g="1.000000" b="1.000000" /> <specular_amount value="0.500000" /> <emit value="0.000000" /> <matmodes value="traceable shadow" /> <specular_brdf value="blender_cooktorr" /> <environment value="env" />

Butth is w il lre s ul tin tw o probl ems: Firs tw ith us ing a nois e m ap you w il le nd up w ith h aving th e nois e patte rn e ve ryw h e re on th e ground pl ane . And th e nois e m ap doe s not cre ate th e de s ire d s urface te xture I am l ook ing for. Se e re nde ring: fak e bum p re fl e ction on pre vious page . Se cond, w h e n you onl y us e bl urre d re fl e ctions re nde re d by Yafray you e nd up w ith a s urface

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onl y s h ow ing th e re fl e ction butnots tructure . Se e re nde ring: true bl urre d re fl e ction on pre vious page . In m y finalre nde r I l e tYafray re nde r th e bl urre d re fl e ctions butI al s o adde d a ve ry fine s tucci bum p m ap to th e norm alch anne lofm y ground pl ane . Th is w il lre s ul tin firs ta ve ry nice bl urre d re fl e ction re nde re d by Yafray and th e s tucci bum p m ap w il lgive th e ground pl ane th e de s ire d s urface s tructure . Th is w il l incre as e th e re nde r tim e a l ot. In cas e you h ave a w e l lw ork ing bum p m ap for th e ground pl ane , itm igh tnotbe ne ce s s ary to us e th e true bl urre d re fl e ction w ith in Yafray s cre e ns h ots ofs tucci bum p m ate rial .

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Profe s s ionalD igitalStudio Re nde ring w ith H D RI IBLand G I

You h ave to pl ay a bitw ith th e re fl e ction val ue s and th e m ate rialprope rtie s be caus e e ve ry ch ange for th e re fl e ctions w il lal s o al te r th e re nde re d col or for th e ground pl ane . At firs tth e re fl e ction and s tucci m ap w as too s trong and dis tracting. In th e l as tre nde ring I l ow e re re d th e re fl e ction val ue as th is al sol ow e re d th e e ffe ctofth e s tucci bum p m ap. Concl us ion W h il e Bl e nde r l ack s m any im portantm ode l ing tool s for CAD/CAM , th is proje ctcl e arl y s h ow s th e s tre ngth ofBl e nde r as a m ode l ing and de s ign tooland Yafray as a ph otore al is tic re nde r e ngine . Both are pow e rfule nough to be tak e n s e rious l y by artis ts w h o w ork in a s e m i CAD/CAM -l ik e e nvironm e nts im il ar to th e one th atI w ork in and w h o ne e d a w e l lbal ance d

s e tofm ode l ing, anim ation, and re nde ring tool s for th e vis ual iz ation. Be caus e al lm y s h ape s are h and crafte d, I do notne e d any toolw h ich is re q uire d for rapid prototyping. Al s o, com pl e x m ode l s can be im porte d from oth e r appl ications to be te xture d in Bl e nde r and th e n re nde re d in Yafray. In te rm s ofph otore al is tic output, Yafray al re ady outpe rform s s om e ofth e indus try s ol utions avail abl e as l ong as you us e itrigh t. Th is can be s e e n as a proofofconce ptth at O pe n-Source s oftw are can re al is tical l y com pe te w ith com m e rcials oftw are s ol utions . W h il e th e re are ofcours e re nde r and m ate rial fe ature s Bl e nde r and Yafray cannots upportat th e m om e nt, itis im portantto k e e p in m ind th atboth program s are curre ntl y unde rgoing a s e rious re cons truction.

11

Bl e nde r is ge tting a ne w node -bas e d m ate rial s ys te m and Yafray continue s to im prove th e ph ys icalaccuracy in re nde ring. As an artis t, I h ope th atfe ature s al re ady pre s e ntin Yafray (s uch as bl urre d re fl e ctions ) w il lbe furth e r inte grate d and m ore acce s s ibl e from Bl e nde r. Th os e m ate rialand re nde r options notonl y incre as e th e pote ntialofth is s oftw are com bination, butcontinue to cl os e th e gap be tw e e n O pe n-Source and com m e rcial s oftw are .

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Profe s s ionalD igitalStudio Re nde ring w ith H D RI IBLand G I

Th e re alfork m ode l(ph otograph )

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13

Sunfl ow Re nde ring Sy s te m Tutorial

th e Fil e ->Exportm e nu as fol l ow s : e ve ryth ing is s e tup corre ctl y. Introduction In th is tutorial , I w il lpre s e nts om e ofth e bas ic fe ature s ofSunfl ow and h ow to us e itfrom Bl e nde r. Sunfl ow is m y ope n s ource re nde ring s ys te m . Itis buil taround a s m al lbutve ry fl e xibl e core w h ich al l ow s itto be com pl e te l y cus tom iz e d. It contains s e ve ralm ode rn al gorith m s th atm ak e ita good candidate for ge ne rating re al is tic im age s . Ith as be e n re ce ntl y conne cte d to Bl e nde r via a s im pl e e xports criptw h ich I w il l be de s cribing.

Ne xt, ge tth e binary re l e as e from th e Sunfl ow w e bs ite (v0.05.5 atth e tim e of th is w riting) and unz ip itto a dire ctory ofyour ch oice . Go to th atdire ctory in com m and l ine m ode and type th e com m and l ine de s cribe d in th e READM E fil e incl ude d in th e dis tribution. You s h oul d s e e th e fol l ow ing w indow appe ar: Firs tRe nde r: A m bie ntO ccl us ion I h ave pre pare d a ve ry s im pl e s ce ne h e re for il l us tration purpos e s . Fe e lfre e to fol l ow al ong w ith your ow n favorite m ode l . H e re is w h atm y s ce ne l ook s l ik e in th e 3D vie w :

Ins tal l ation Sunfl ow is w ritte n in Java. Th is m e ans you w il l ne e d to dow nl oad and ins tal lth e Sun JRE (or JDK ) ifyou don'th ave ital re ady. Go to h ttp://java.s un.com /and fol l ow th e ins tructions for your particul ar ope rating s ys te m (O S X us e rs w il lne e d to go to th e Appl e w e bs ite ). Sunfl ow re q uire s Java ve rs ion 5 (s om e tim e s cal l e d 1.5) or h igh e r. O nce you are s e tup, go to a com m and prom pt and type : java -ve rs ion Ifth e corre ctve rs ion num be r appe ars

You are now re ady to re nde r your firs tim age !

Final l y, ge tth e bl e nde r e xporte r s criptfrom th e Sunfl ow w e bs ite and ins tal litinto to your bl e nde rs (Ins ide your bl e nde r ins tal l ation fol de r) s cripts fol de r. Ne xtw h e n you s tart Bl e nde r you s h oul d s e e an option appe ar in

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14

Sunfl ow Re nde ring Sy s te m Tutorial

Go to th e Fil e -> Exportand pick th e Sunfl ow Exporte r you jus tins tal l e d. Itw il lbring up th e fol l ow ing UI in th e s criptw indow :

your s ce ne . Th e de faul tofz e ro corre s ponds to infinite l yl ong rays .

W e are jus tgoing to ch ange a fe w s e ttings th e firs ttim e around. O ur goalis to do a s im pl e am bie ntoccl us ion re nde r to ge ta fe e lfor th e proce s s . Don'tw orry aboutth e m any diffe re nt s e ttings you s e e , w e w il lcove r m os tofth e m s oon.

Now go to th e Sunfl ow w indow you l aunch e d e arl ie r and ope n th e s ce ne fil e you jus tw rote out. Ifl oading s ucce e ds w ith oute rrors , th e Re nde r m e nu option w il lnow be e nabl e d.

In th e AO O ve rride tab, cl ick th e 'Am b O cc' toggl e . Th is is s im pl y te l l ing th e e xporte r th at w e w antto ove rride al ls h ading in th e s ce ne w ith th e pre s cribe d am bie ntoccl us ion s h ade r. Th e m os tim portantoptions are s am pl es (num be r ofrays trace d to cal cul ate th e occl us ion) and th e dis tance s e tting (h ow far to l ook for oth e r obje cts ). For now , l e ave th e num be r ofs am pl e s as itis , and s e tth e dis tance to a re as onabl e val ue for

Now h itth e Exportbutton and pick a l ocation to putth e e xporte d s ce ne fil e . You can l ook atBl e nde r's output w indow to s e e th e s te ps th e e xporte r is tak ing. Itm ay tak e a fe w s e conds to w al k th rough your s ce ne ifyou h ave m any obje cts . W h e n th e fil e is e xporte d you w il lbe s e ntback to th e e xporte r options .

Se l e ctRe nde r -> IPR firs t. Th e im age w il ls tart re nde ring in a ve ry bl ock y form and progre s s ive l y re fine its e l f. Afte r jus ta fe w s e conds , you s h oul d al re ady s e e w h atth e finalim age is going to be l ik e . You m ay cance l th e re nde r atanytim e . In m os tcas e s , l ess th an 10% ofth e im age is ne e de d be fore you are re ady to l aunch th e ful lre s ol ution re nde r. Now s e l e ctRe nde r -> Re nde r. Th e im age w il l re nde r in s m al lbuck e ts th is tim e . Ifyou h ave a m ul ti-proce s s or m ach ine you w il ls e e s e ve ral buck e ts re nde ring atonce . Afte r a fe w

s e conds you s h oul d s e e s om e th ing l ik e th e s ce ne be l ow . Congratul ations ! You jus tre nde re d your firs t im age w ith Sunfl ow .

Your im age w il lprobabl y be nois y and h ave m any s m al lartifacts . Don'tw orry. W e w il l l e arn h ow to e nh ance th e q ual ity ofth e im age s oon. Now , l e t's m ak e our s ce ne a bitm ore inte re s ting by adding s om e l igh ts and m ate rial s to it!

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15

Sunfl ow Re nde ring Sy s te m Tutorial

Ligh ts and M ate rial s Go back to bl e nde r and as s ign s om e uniq ue m ate rial s to e ach s urface . K e e p in m ind th at th e e xporte r doe s notye ts upportth e ful l range ofBl e nde r s h ade rs and te xture s . For now , w e w il ljus tbe cre ating re gul ar diffus e m ate rial s . For e ach m ate rial , s im pl y as s ign a uniq ue col or. Th is is th e onl y attribute th atis re ad by de faul t, al loth e r options are ignore d. Th e re are a fe w e xce ptions to th is rul e to ge ne rate oth e r Sunfl ow s h ade rs , but w e w il lcove r th e m l ate r on. Ne xt, w e ne e d s om e l igh ts . Th e e xporte r curre ntl y onl y s upports l am ps and s q uare are a l igh ts . Are a l igh ts w il lgive you nice s oft s h adow s atth e e xpe ns e ofadditionalre nde r tim e . M y s ce ne w ith bas ic s h ade rs and l igh ts now l ook s l ik e on th e im age atrigh t. O nce you are h appy w ith your s ce ne , tim e to e xportagain! Th is tim e , l e t's try to unde rs tand th e various s e ttings and h ow th e y affe ctim age q ual ity. Th e m os tim portantare probabl y th e AA s e ttings . Th e m in and m ax val ue s controlh ow m uch com putation goe s into e ach pixe l . Ne gative val ue s m e an com putations w il lbe inte rpol ate d acros s s e ve ralpixe l s , pos itive val ue s m e an m ore cal cul ations w il lbe done pe r pixe l . Z e ro m e ans a s ingl e com putation is done pe r pixe l . For e xam pl e : th e de faul t

val ue s of-2 and 0 m e an th atth e re nde re r w il l s tartby cal cul ating e ve ry 4th pixe l , and adaptive l y cal cul ate dow n to th e s ingl e pixe l l e ve lw h e re itis ne e de d. Th is tim e , try s e tting your AA val ue s to 0 and 2. Each pixe lw il lnow be s h ade d atl e as tonce , and up to 16 tim e s (l e ve l2). Ifw e cal cul ate m ore th an one val ue pe r pixe l , w e w il lne e d to ave rage th e m toge th e r. Th e w ay th is is done is control l e d by th e im age fil te r s e tting. Le t's pick th e 'M itch e l l ' fil te r as itprovide s a nice s h arpe ning ofth e im age . Th is particul ar fil te r h as a fixe d w idth and h e igh t, s o th os e s e ttings w il ldis appe ar from th e dial og w h e n itis s e l e cte d. Ligh ts e rve r s e ttings l e tyou controlh ow m any rays are us e d pe r l igh t. Th e de faul tof16 is a bith igh butus ual l y give s good q ual ity. Th e GI tab control s gl obalil l um ination. Th is is an advance d topic w e w il l e xpl ore in th e ne xts e ction. Le ave al l th e control s atth e ir de faul tval ue s for now . Th e Acce l e rator tab contains s e ttings w h ich h ave no im pacton im age q ual ity butcan m ak e dras tic diffe re nce s in im age cal cul ation tim e . Th e de faul t acce l e rator is th e k dtre e and is us ual l y

th e be s tch oice . You can e xpe rim e ntw ith diffe re ntacce l e rator type s and s e e w h ich one provide s th e fas te s t re s ul ts for your s ce ne . You can al s o adjus tth e buck e torde r in th is tab. Sw itch to s piralth is tim e to h ave th e im age com pute d from th e ce nte r out.

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16

Sunfl ow Re nde ring Sy s te m Tutorial

Unde r th e l igh ttab, w e h ave th e option of adjus ting th e s tre ngth ofal ll igh ts in th e s ce ne . Since Sunfl ow us e s m ore ph ys ical l y bas e d cal cul ations th an Bl e nde r, th e l igh tpow e rs w il l notus ual l y m atch . Th is gl obals cal e factor can hel p you com pe ns ate for th is . I s e tm ine to 5, butth is w il lvary from s ce ne to s ce ne . Note th atth e s cal e factor onl y affe cts are a l igh ts . Final l y, re m e m be r to de s e l e ctth e 'Am b O cc' button from th e AO O ve rride tab ifitw as s til l sel e cte d from th e pre vious e xport. W e can now e xportand re nde r again. Ifyou e xportto th e s am e l ocation as be fore (ove rw riting th e ol d fil e ), you can s im pl y us e th e Fil e -> Re -ope n m e nu option in th e Sunfl ow GUI to q uick l y re l oad your s ce ne .

Us e th e IPR fe ature again to s e e w h atyour s ce ne l ook s l ik e q uick l y. You w il lprobabl y ne e d a coupl e ofe xportcycl e s be fore you ge t th e l igh tinte ns itie s jus trigh t. H e re is m y re s ul t (Im age l e ftbottom ). De s pite th e s ofts h adow s , th is im age is n'tve ry re al is tic ye t. I w il ls h ow you h ow to addre s s th is in th e ne xts e ction. Gl obalIl l um ination Te ch niq ue s As I m e ntione d in th e introduction, Sunfl ow is a ve ry cus tom iz abl e re nde re r. Itis th e re fore abl e to incorporate m any diffe re ntGI al gorith m s into one coh e re ntfram e w ork . Th is give s th e artis ts diffe re ntw ays to ach ie ve th e ir goal s and m ak e s itpos s ibl e for de ve l ope rs to introduce ne w al gorith m s , w ith outbre ak ing ol de r s ce ne s . I w il lnow brie fl y de s cribe one ofth e m e th ods ofcal cul ating gl obal il l um ination: path tracing. Th is is th e m os taccurate and e as ie s tm e th od to l e arn. Th e catch is th atitcan tak e q uite l ong to ach ie ve h igh q ual ity re s ul ts . In th e e xporte r, go to th e GI tab and e nabl e th e path button. Th e al gorith m is control l e d by tw o param e te rs : s am pl es and bounce s . Th e firs tde faul tto 32 and control s th e q ual ity ofth e re s ul t. Th e s e cond de faul tto 1 and control s h ow m any bounce s th e l igh tis al l ow e d to m ak e .

Le ave th e val ue s atth e ir de faul ts for now to s e e th e ir e ffe ct. Since th is al gorith m w il l produce ve ry nois y re s ul ts , go to th e AA tab and s e tboth th e m in and m ax to 0. Th is w il l force onl y one s am pl e to be tak e n pe r pixe l , w h ich avoids th e anti-al ias ing from be ing force d to s upe r s am pl e e ve ry s ingl e pixe l be caus e ofth e nois e . You m ay al s o w antto s e tth e fil te r back to box (w idth and h e igh t1) to avoid introducing artifacts by fil te ring th e nois e . Exportand re nde r again. I adde d s om e w al l s be h ind m y s ce ne to s e e th e e ffe ctofth e bounce s . Com pare th e s e tw o re nde rs w ith and w ith outgl obalil l um ination:

Gl obalil l um ination re fe rs to m e th ods w h ich are bas e d on ph ys icalcom putation ofl igh ting in a s ce ne by tak ing into accountth e e ffe cts ofl igh tbounce s on and offth e 3d s urface s . Itprovide s th e m os tre al is tic l igh ting s im ul ation ofin CG.

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and be tw e e n th e obje cts . You m ay find ith ard to ge trid ofth e nois e in th e im age in a re as onabl e am ountoftim e , e ve n ifyou m ak e th e num be r ofs am pl e s q uite h igh . Th is is a th e ore ticall im itation ofth e path tracing al gorith m . Ph oton m aps and irradiance cach ing are tw o al gorith m s th atw h e n com bine d can yie l d a m uch m ore e fficie nt s ol ution;h ow e ve r th e y are m uch trick ie r to s e tup, e ve n for e xpe rie nce d us e rs . Sce ne w ith GI

Rath e r th an go into th e de tail s ofth e s e advance d m e th ods , itm igh tbe be tte r to k now th ats im pl e r and m ore e fficie ntal gorith m s e xis t th atw il lve ry l ik e l y appe ar in Sunfl ow s oon. Im age bas e d l igh ting In th is s e ction w e w il lcove r th e us e ofH DRI e nvironm e ntm aps for l igh ting. Back in your bl e nde r s ce ne , l oad in a l ongitude -l atitude H DRI e nvironm e ntm ap as a te xture atth e w orl dl e ve l . Be s ure to unch e ck 're l ative path s ' wh enl oading th e m ap. Re nam e th e te xture obje ctto 'ibl l igh t' as s h ow n. Th is l e ts th e e xporte r k now you w antto tre atth is m ap as an e nvironm e ntl igh ts ource .

Sce ne w ith no GI Notice h ow th e s h adow e d re gions are no l onge r com pl e te l y dark and h ow w e obtaine d s om e s ubtl e col or bl e e ding on th e fl oor

17

Sunfl ow Re nde ring Sy s te m Tutorial

Go ah e ad and h ide al lth e l igh ts you w e re us ing be fore (th e e xporte r re s pe cts Bl e nde r l aye rs ), and m ak e s ure your s ce ne is 'ope n'. Th is type ofl igh ting as s um e s th e l igh tis com ing from infinite l y far aw ay, s o its be s t s uite d to outdoor re nde rings . Indoor s ce ne s w il lpe rform ve ry poorl y w ith th is te ch niq ue . Sunfl ow approxim ate s th e e nvironm e ntm ap w ith a fixe d num be r ofdire ctionall igh ts . Th is is control l e d by th e 'Dire cts am pl e s ' s e tting in th e e xporte r. Us ing th e de faul tof16 you w il l probabl y s e e s om e s h arp e dge s to th e s h adow s from th e individuall igh ts us e d. Sim pl y incre as e th e num be r ofl igh ts am pl es untilth e s h arp s h adow boundarie s are de cre as e d to an acce ptabl e l e ve l . Exporting and re nde ring again, you s h oul d e nd up w ith s om e th ing l ik e th is :

W O RK SH O P3D -

18

Sunfl ow Re nde ring Sy s te m Tutorial

Th is im age is q uite re al is tic, e ve n th ough w e h ave notus e d any gl obal il l um ination. O fcours e you m ay e nabl e path tracing as w e did be fore to s im ul ate th e e xtra bounce s ofl igh t. Gl os s y m ate rial s Final l y, l e t's m ak e our s h ade rs a l ittl e m ore inte re s ting. Up untilnow w e h ave us e d com pl e te l y diffus e s h ade rs . Le t's s tartw ith th e s h iny s h ade r. Its im pl y adds a th in re fl e ction coaton top ofth e diffus e col or. Re nam e one ofyour obje cts m ate rial s s o th atits nam e s tarts w ith 's fs h iny'. Th e e xporte r w il lnow re ad th e 'RayM irr' attribute to de te rm ine th e am ount ofre fl e ction to appl y. Ne xtis th e ph ong s h ade r w h ich provide s bl urry re fl e ctions . Re nam e th e m ate rialyou w is h to e dits o th atits tarts w ith 's fph ong'. Th e s pe cul ar col or now control s th e am ountof re fl e ction w h il e th e 'h ard' val ue control s th e bl urrine s s . H igh e r h ardne s s val ue s re s ul tin s h arpe r re fl e ctions . For m y s ce ne I us e d val ue s ranging from 5 to 50. Now th atw e h ave adde d s e ve rall aye rs of re fl e ctions , w e ne e d to pay atte ntion to th e 'M ax De pth ' s e tting in th e e xporte r dial og. Th is control s h ow m any l e ve l s ofre fl e ctions are al l ow e d. Th e de faul tof9 is rath e r h igh s o w e w il lre duce itto 3 th is tim e .

H e re is th e finalre s ul t, re nde re d w ith th e im age bas e d l igh ting from th e pre vious s e ction: Concl us ion I h ope you've e njoye d th is q uick tour ofs om e th e fe ature s ofth e Sunfl ow re nde ring s ys te m . O ne tutorialis note nough to cove r e ve ryth ing th atis pos s ibl e w ith th is s oftw are . M any m ore th ings are s upporte d, l ik e te xture s , re fractions , de pth offie l d, caus tics , and e ve n proce dural s h ading. Pl e as e vis itth e Sunfl ow h om e page (h ttp://s unfl ow .s ource forge .ne t) and th e El ys iun forum s (h ttp://w w w .e l ys iun.com /) to l e arn m ore . H appy re nde ring!

Ch ris toph e r K ul l a is th e prim ary de ve l ope r ofth e Sunfl ow Re nde ring s ys te m . In h is day job h e w ork s as a s oftw are de ve l ope r for Re e lFX Cre ative Studios in Dal l as , Te xas , w ork ing on com m e rcial s , dire ct-toDVD and anim ate d fe ature fil m proje cts . h ttp://s unfl ow .s ource forge .ne t

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G I and H D RI l igh ting in Y afray

Introduction Th e re are a m ul titude ofw ays to l igh ta s ce ne , from a fe w s im pl e s potl igh ts , th rough are al igh ts and com pl exl igh trigs upto diffe re nt form s ofgl obalil l um ination. H e re I w il lbe dis cus s ing th is l atte r option us ing Yafray for re nde ring, from ins ide Bl e nde r. Firs tI'd l ik e to addre s s th e com m on m is conce ption th atGI is s om e m agic 'm ak e re al is tic re nde ring' button. Itis s im pl y a type ofl igh ting m ode lth atis m ore advance d th an th e good ol d s potl am ps , and m ore ph ys ical l y accurate . Itw il lnot autom atical l y m ak e a nice im age for you, itw il l s im pl y give you a h e ad s tartby be ing a s ubs titution for a ve ry com pl exl igh ting rig w ith doz e ns ofl am ps th atw oul d ne e d to be pl ace d

by h and. Itth e re fore s ave s tim e (and tim e =m one y). Itbas ical l y give s you a bas e fil l l igh t, w ith an e ve n l igh tdis tribution, and a nice naturall ook . Th is can (and s h oul d) be com pl e m e nte d w ith traditionall igh ts . Be s ide s th e l igh ting, th e GI re nde ring al gorith m is al s o re s pons ibl e for col our bl e e ding be tw e e n obje cts (h ard to fak e w ith out GI), and caus tics (ne ar im pos s ibl e to fak e ). H ow e ve r, GI is s l ow e r th an raytracing and m uch s l ow e r th an s canl ine re nde ring, and is th e re fore onl y for finalre nde ring for s til l s . It can'tre al l y be us e d for anim ations (ye t), not onl y be caus e ofre nde ring tim e , butbe caus e l igh t/dark s pots are random l y re nde re d (s am pl e d) and th e y jum p around from fram e to fram e .

19

Firs tw e 'l ll ook atth e GI s e ttings for Yafray, and th e n I'l lde s cribe a typicall igh ting s e tup th atI us e for productvis ual iz ation. Gl obalil l um ination is diffe re ntfrom raytracing. In th e l atte r a ray is trace d from th e cam e ra to an obje ct, th is can be re fl e cte d/re fracte d, and th e n trace d to al ll igh ts th atare vis ibl e . Th is give s you re fl e ction, re fraction and (h ard) s h adow s . GI, on th e oth e r h and trace s th e path ofth e ph otons th e m s e l ve s from th e l am ps to th e obje cts , bouncing be tw e e n obje cts in th e s ce ne . Th is give s you re fl e ction, re fraction AND col our bl e e ding, s ofts h adow s , caus tics (im pos s ibl e w ith raytracing) and ge ne ral l y a nice r l ook . Th e origin ofth e l igh tin GI can be a l am p, or any obje ct. For outs ide s ce ne s , th e w h ol e back drop (w orl d) can e m it l igh t. Since Bl e nde r doe s nots upportGI ye t, I us e Yafray.

W O RK SH O P3D -

20

G I and H D RI l igh ting in Y afray

GIs e ttings Firs t, m ak e s ure th atyou h ave Yafray ins tal l e d, and its l ocation adde d to your O S's 'path ' variabl e (s e e th e Yafray re adm e !). In Bl e nde r, go to th e re nde r buttons , and in th e drop-dow n l is tunde r th e l arge RENDER button, s e l e ctYafray. Th is s h oul d ope n up tw o e xtra s e ttings pane l s : "Yafray" and "Yafray GI". In th e Yafray pane l , th e XM Lbutton s h oul d be turne d off, th is al l ow s you to s e e th e re nde r in progre s s . Th e tw o buttons be l ow al l ow you to s pe cify th e antial ias ing. O th e r buttons be l ow th e s e are n't im portantnow , th e y don'tne e d to be ch ange d. Th e oth e r pane l , "Yafray GI" is m ore im portant. Th e "M e th od" drop-dow n l is tal l ow s you to s e l e cte ith e r None for no GI, Sk yDom e for a m e th od s im il ar to Bl e nde r's Am bie nt O ccl us ion, and Ful lfor th e prope r gl obal il l um ination re nde ring. Se l e cting Ful lw il lope n up ne w buttons on th e bottom . Th e Qual ity s e tting w il lde te rm ine th e (gue s s w h at!) q ual ity as w e l las s pe e d ofth e re nde r, a s e tting ofm e dium /h igh s h oul d be e nough for m os ts ituations . Ifth e re are s m al lface s , de tail e d m ode l s , or s urface s ve ry cl os e to e ach oth e r, you m igh tne e d to s e tth e q ual ity h igh e r to ge trid ofre nde r artifacts . A com pl e te GI s ol ution can be painful l ysl ow to re nde r (h ours ), s o s om e trick s can be us e d to s pe e d itup. Turn on both th e Cach e and th e

Ph otons buttons in th e Yafray GI pane l . Th e ph oton cach e w il ls pe e d up th e re nde r ove r te n tim e s ! H ow e ve r, itw il ll e ad to s om e brigh t/dark s pots on th e finalre nde r. Incre as e th e Qual ity to ge trid ofth e s e , or ch ange th e "Re f" button. Ifyou s e tth e "Re f" (re fine m e nt) to anyth ing oth e r th an 1 (I us e 0.1), itw il l cal cul ate th e ph oton m ap tw o tim e s be fore th e finalre nde r. Th e s e cond pas s doe s m ore cal cul ations in th e parts ofth e picture th at h ave m ore de tail , and th e finalre s ul tw il l th e re fore be be tte r. Th e oth e r im portants e ttings are : "Em itPw r" and "GI Pw r". Th e e m itpow e r de te rm ine s h ow brigh te m itting obje cts , are al igh ts and th e back ground are . GI pow e r de te rm ine s h ow m uch "e ne rgy" (l igh t) th e s e e m itte rs w il le m it. It is us ual l y e nough to ch ange th e GI Pow e r s e tting to m ak e your s ce ne dark e r or brigh te r. Em itte rs To us e GI, you ne e d to h ave s om e l igh te m itte rs in your s ce ne . Ligh te m itte rs in Bl e nde r/Yafray can be th e fol l ow ing: are al igh ts , obje cts w ith a m ate rialEm itval ue m ore th an 0, and th e back ground. Th e s im pl e s tth ing to do is s e t th e back ground to any col our th atis n'tbl ack . Th e back ground

w il le m itfrom al ldire ctions e ve nl y, s im il ar to an ove rcas tday outs ide . You can al sol oad a H DR l igh tprobe , w h ich de te rm ine s w h at col oure d l igh tcom e s from w h ich dire ction. Now , l e ts try s om e l igh ting! I w il lus e a s ce ne I did nottoo l ong ago, itis a de s ign for a fol d-up w ine h ol de r. You can s e e th e finalim age h e re , itis for productvis ual iz ation. Th e re fore th e m os tim portantpartofth e im age is th e productits e l f, and noth ing e l s e s h oul d be pre s e ntto draw th e vie w e rs ' atte ntion aw ay, note ve n a back ground s ce ne . ProductVis ual iz ation I - "W h ite Space "

W O RK SH O P3D -

21

G I and H D RI l igh ting in Y afray

Th is is one ofm y favorite s e tups , for l ack ofa be tte r te rm I cal l e d it"w h ite s pace ", th e productis on a com pl e te l y w h ite ground, w ith a w h ite back ground, ye titdoe s n'tjus tfl oatin s pace , ith as s h adow s . Itl ook s ve ry good printe d on pape r, as w e l las in any docum e ntor oth e r w h ite back ground (a w e bpage for e xam pl e ), cre ating th e im pre s s ion th atth e obje ctits e l fis s itting th e re on th e pape r. Ifyou l ook cl os e r, you can s e e th e re are tw o type s ofs h adow h e re . Th e h ard s h adow com e s from a s un l igh t, butyou can us e any oth e r type ofl igh tth at cas ts s h adow s . NO TE: e xce ptare al igh ts ! Are al igh ts actas ph oton e m itte rs w h e n GI re nde ring in Yafray, and notas norm all igh ts ! Th e nice s ofts h adow s are th e re s ul tofGI. Th e s ce ne

Th e s ce ne , be s ide s th e productits e l f, is s im pl y a w h ite pl ane , and a s un l am p, noth ing m ore , ve ry s im pl e.

l am p w ith Raytrace d s h adow s turne d on. Itis sl igh tl y ye l l ow is h in col our, w ith a pow e r of0.6.

Th e ground.

Th e W orl d

Th e w h ite pl ane doe s n'te xte nd too far, jus tfar e nough to catch al lth e s h adow s ofth e obje cts . Itis com pl e te l y w h ite , and th e Re fl e ctivity is 1.0. Note th atth e option "O nl y s h adow " doe s n'tw ork w ith Yafray. Th is m e ans th e e dge s ofth e pl ane w oul d be vis ibl e in th e finalre nde r, w h ich is notgood! Th is can be fixe d in th e re nde r s e ttings , s e e be l ow .

Ve ry s im pl e again, th e w orl d is one col oure d, a ve ry s l igh tl y bl ue is h w h ite .

Th e l igh t Th e re is onl y one l igh tin th e s ce ne , a s un

Re nde r s e ttings

W O RK SH O P3D -

G I and H D RI l igh ting in Y afray

IM PO RTANT! Itis re al l yl am e , and I h ave s e e n bad e xam pl e s ofitm any tim e s , w h e n a productis s h ow cas e d on a gre y pl ane , fl oating in s pace , or atl e as ton s om e s ortof back ground. Th is gre y pl ane s h outs CGI. It's im portantth atyou can'ts e e th is bas e pl ane , it s h oul d bl e nd into th e back ground. In th is e xam pl e I us e d a w h ite pl ane , bute ve n a w h ite pl ane s om e tim e s is re nde re d gre y atth e e dge s . Th e back ground its e l fis s l igh tl y bl ue and notw h ite . So th e trick to h ave th is "W h ite Space " e ffe ctis to s e tth e Em itPw r in th e Yafray GI s e ttings above 1.

q ual ity/s pe e d trade off. And s e e h ow m uch q ual ity w e h ave ach ie ve d w ith a ve ry s im pl e s e tup! ProductVis ual iz ation II - H DR Ligh ting Ins te ad ofa pl ain w h ite -is h w orl d col our, you can s e ta H igh Dynam ic Range l igh tprobe for th e back ground. Th is w il lvary th e l igh tcol our

Ittak e s s om e e xpe rim e ntation for th e righ t s e ttings , s o th atyou can'ts e e th e e dge ofth e bas e pl ane , butitdoe s n'tgl ow in an unnatural w ay e ith e r. A s e tting of1.20 s e e m s to w ork wel l . GI pow e r is 0.80. Ifyou m ak e th e s un l am p brigh te r, th e n de cre as e th e s e s e ttings , if its dark e r th e n incre as e th e s e . M ak e s om e l ow re s ol ution te s tre nde rs . Cl ick and h ol d th e l e ftm ous e button on th e re nde r, th is w il ls h ow th e col our ofth e give n pixe lin th e bottom l e ftcorne r. Drag th e m ous e around, and m ak e s ure th atboth th e back ground, and th e bas e pl ane is R: 255, G: 255, B: 255. Th e n you're re ady for th e h igh re s finalre nde r! M ak e s ure to s e tth e q ual ity to M e dium or H igh , th e Re fval ue to s om e th ing oth e r th an 1, and turn on Antial ias ing, in th is e xam pl e I us e d 2 pas s e s w ith 4 s am pl e s e ach , th is is th e s e tting I us ual l y us e , itis a good

and inte ns ity acros s th e virtuals k y, m ak ing a m ore natural , s m ooth l ook . To cl arify th e tw o te rm s , H DR m e ans h igh -dynam ic range im age , w h e re ins te ad ofRGB val ue s from 0 to 255, fl oating pointnum be rs w ith be tte r pre cis ion, and a h igh e r "dynam ic range " are us e d to s tore th e l um inos ity (l igh te m is s ion) of

22

e ach pixe l . Ligh tprobe m e ans th e im age is a com pl e te 360-de gre e panoram ic picture ofth e e nvironm e nt. Th e proce s s ofm ak ing H DR l igh tprobe s is outs ide th e s cope ofth is tutorial , s o I w il ljus ts ay e ith e r dow nl oad one ofth e s e ve ralH DR probe s avail abl e on th e ne t(s e e h ttp://w w w .de be ve c.org for s om e s tarte rs ), or m ak e your ow n. M ak e s ure itis in th e l igh tprobe form at(ak a. angul ar m ap), as oppos e d to: ve rticalcros s , l atitude /l ongitude , or s om e oth e r panoram ic form at. Th is ne xts te p can be s k ippe d, butI h igh l y re com m e nd it. Th e probl e m w ith GI il l um ination w ith Yafray is th atfor a a fas t re nde ring, itus e s s om e random s am pl e s of th e e nvironm e nt. A nice and s h arp H DR im age can h ave diffe ring l igh tval ue s in a s h ort inte rval , ie : too m uch contras t. W ith jus ta fe w s am pl e s , s om e s am pl e s w il l fal lonto a ve ry brigh tpixe l , and s om e w il lfal l onto a ne arby dark e r pixe l , and th is w il lre s ul t in a "s potty" re nde r. I s ol ve th is probl e m by bl urring th e originalH DR m ap. From h ttp://w w w .h drs h op.org, you can dow nl oad H DRSh op v1 for fre e . O pe n your l igh tprobe , and in th e Fil te rs m e nu, s e l e ctGaus s ian bl ur, and bl ur th e im age , us ing a val ue of4-5 for s m al l e r m aps : 512*512, to 12-15 for h igh e r re s ol ution m aps , l ik e 1512*1512. Re s ave it w ith a diffe re ntnam e .

W O RK SH O P3D

- G I and H D RI l igh ting in Y afray

Loading th e H DR probe Go to th e te xture buttons , and s e l e ctth e gre e n "W orl d" button. Se tte xture type to Im age , and l oad th e *.h dr fil e l ik e any oth e r im age . Go to th e w orl d button, and in th e M ap To pane l ,set m apping to Angul ar m ap, and th e outputto H ori, Z e nUp and Z e nDow n. Yafray w il l autom atical l y s e e th atyou h ave a H DR w orl d te xture , and w h e n GI is turne d on, it autom atical l y us e s th atim age for l igh ting.

s h adow coul d be pl ace d anyw h e re . H ow e ve r, m os tH DR probe s h ave one or m ore conce ntrate d l igh ts ource s . Firs tre nde r th e s ce ne w ith onl y th e GI l igh ting and no l am ps . Se e w h ich w ay th e s ofts h adow s are cas t, and th e n pos ition th e s un l am p accordingl y. You m igh tne e d s e ve ralte s tre nde rs to ge tth e h ard s h adow pointing th e righ tw ay. I us ual l y us e ve ry s ubtl e, w e ak l igh t(s ) w ith H DR m aps , th e e ne rgy s h oul d be around 0.2-0.4, notm ore .

Sce ne s e tup Sim il ar to th e pre vious e xam pl e . Th e bas e pl ane is note nough h ow e ve r, as you w il ls e e its e dge in th e re nde r. To fix th is , m ak e th e farth e r e nd ofth e pl ane curve up into th e air, h igh e nough to bl ock al lofth e cam e ra's fil ed ofvie w . M ak e s ure th is curve s tarts farth e r th an th e s h adow s ofth e obje ct, oth e rw is e you w il ls e e th e s h adow curve up unnatural l y into th e air. Se e top righ tim age .

Re nde r s e ttings Th e y s h oul d be s im il ar to th e firs t m e th od, e xce ptfor th e GI Pow e r s e tting. Th is can vary a l otw ith th e give n H DR m ap you are us ing, de pe nding on h ow brigh titis . Do s om e l ow re s q uick re nde rs to find th e righ tbrigh tne s s . Som e dark e r m aps ne e d 1-1.5 atth e m os t, w h il e th e brigh te r one s m igh tonl y ne e d a GI Pow e r of0.2. And th e n com e s th e finalre nde r! H e re is m y te s ts ce ne w ith a s uns e tH DR probe m ade w ith Te rrage n. Th is s am e q ual ity w ith outGI w oul d ne e d a fe w doz e n l am ps , al l s e tup prope rl y, s o w e cl e arl y s e e th e advantage s .

Ligh ts Th e "W h ite Space " m e th od above h ad a com pl e te l y uniform w h ite l igh t, w h ich m e ans th e s un l am p us e d for th e additionalh ard

Notonl y do H DR m aps provide th e bas e l igh ting ofa s ce ne , butth e y al s o provide a re al is tic e nvironm e ntth e obje cts can re fl e ct. Th e y can al s o be th e back ground, h ow e ve r

23

m os tH DR probe s are too l ow -re s to provide a nice back ground im age . Ins te ad, itis pre fe rabl e to us e a ph oto ofth e original l ocation for a back ground. Th is te s tim age s h ow s one ofm y ow n probe s in action, al ong w ith a ph oto back ground tak e n atth e s am e l ocation. Note th atins te ad ofa gre y pl ane w h ich s cre am s CGI, I us e d a s tone pe de s tal , m ak ing itbl e nd in be tte r.

W O RK SH O P3D

- G I and H D RI l igh ting in Y afray

Th is w as jus tone s m al lportion ofw h atyou can do w ith gl obalil l um ination, you can al s o us e itfor indoor s ce ne s . Try pl acing e m itting pl ane s or are a l am ps in your s ce ne . For caus tics , add "ph oton l am ps ", w h ich are avail abl e in th e Lam p s e ttings in Bl e nde r. Expe rim e nt. H ave fun!

Il ive in H ungary, and am curre ntl y s tudying indus trialde s ign e ngine e ring atth e Budape s t Unive rs ity ofTe ch nol ogy and Econom ics . Som e ofm y h obbie s are : 3D graph ics ofcours e :), conce ptde s ign/productde s ign, pl us w atch ing good m ovie s , going outw ith frie nds , h anging out on e l ys iun and oth e r forum s , draw ing. h ttp://yafray.org

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W O RK SH O P3D -

Y afray caus tics s am pl e r tutorial

ins tal l e d, you w il lbe re ady to be gin re nde ring your Firs tCaus tics s ce ne ! Us ing Caus tics Th e s e tup ofth e s ce ne is ve ry s im pl e . W e w il l be us ing th e de faul ts ce ne w ith s om e l am p pl ace m e ntch ange s . Ste p1. Launch Bl e nde r. Ste p2. Go to th e Re nde r Buttons [F10] and s w itch th e Re nde re r from Bl e nde r Inte rnalto th e Yafray Re nde re r.

In th is tutorialw e are going to e xpe rim e ntw ith Yafray and Bl e nde r and l e arn h ow th e y inte racttoge th e r. W e w il lcre ate a s im pl e caus tic e ffe ctus ing de faul ts e ttings . Furth e r e xpe rim e ntation can be us e d to cre ate bre ath tak ing im age ry! Ge tting Starte d Firs t, w e w il lne e d to h ave th e l ate s tve rs ions of Bl e nde r [Bl e nde r 2.41] and Yafray [Yafray 0.7] both ins tal l e d on your com pute r. You can ge tth e s e from w w w .bl e nde r.org and w w w .yafray.org re s pe ctive l y. O nce

Th is w il lcre ate s om e ne w pane l s in th e Re nde r Buttons , EditButtons , M ate rial Buttons , and th e Lam p Buttons . W e w il lge tto th e s e ne w pane l s s h ortl y. Ste p3. In th e 3D W indow Se l e ct[RM B] th e de faul tcube . Go to th e M ate rialButtons [F8]. Th e Raytracing Pane lintroduce s th e avail abl e

25

Yafray fe ature s . W e w il lbe m ak ing a cl e ar gl as s us ing de faul ts e ttings for gl as s in m ate rialpane l . Se l e ct'Cl e ar Gl as s ' from th e drop dow n m e nu. Se tth e re m ainde r ofyour m ate rials e ttings to Fig. 1. You m igh tw antto be ve lth e e dge s ofth e m e s h . For th is obje ctI us e d Subdivide M ul ti 3X and th e n adde d a 0.100 Be ve l2X and th e n appl ie d Se tSm ooth . A bas ic be ve lw oul d w ork jus tas w e l l . W atch th e im age atbottom . Ste p4. In th e 3D W indow s w itch to Top Vie w [Num 7] and Add [Space Bar] a Pl ane [Add>>M e s h >>Pl ane ] to th e s ce ne , th is is going to be th e fl oor in th e s ce ne .. ExitEdit M ode [Tab]. You w il lne e d to M ove [G] itdow n al ong th e Z -axis [Z ] one grid unit[H ol d Ctrl ]s o th atitis fl us h w ith bottom ofth e Cube . O pe n th e Trans form Prope rtie s Pane l[Nk e y] and s cal e th e Pl ane to 50 units or s im pl y pre s s [S] and s cal e itto s pre ad up to th e cam e ra vie w . Go to th e M ate rialButtons [F8] and Add a Ne w M ate rial .

W O RK SH O P3D -

Y afray caus tics s am pl e r tutorial

M ak e s ure to h ave th e Trace Sh adow fe ature e nabl e d in th is m ate rial . You can e ve n appl ya te xture ifyou l ik e . I us e d a l igh tbl ue s ol id col or for th is m ate rial . Ste p5. In th e 3D w indow s w itch to Top Vie w [Num 7] and s e l e ct[RM B] th e de faul tl am p and de l e te [De l ] it. Now pl ace your 3D Curs or at approxim ate l y 0,4,2 XYZ Gl obalcoordinate s . Pre s s [Space Bar] to add an Are a Lam p Add>>Lam p>>Are a. Th e l am p s h oul d be autom atical l ysel e cte d, butifnots e l e ctitand th e n bring up th e Trans form Prope rtie s Pane l

[N]. Se tth e Location XYZ coordinate s to 0,4,2 re s pe ctful l y in th e trans form pane l . Se tth e Rotation XYZ coordinate s to 65,0,180 re s pe ctful l y. In th e M ate rial /Lam p Buttons s e t th e pow e r to 0.250. Give itth e s h ape ofa Sq uare 3.0. Se tth e 'Sh adow Sam pl e s ' at10 or gre ate r. Ste p6. Dupl icate [Sh ift+ D] th e Are a Ligh tth e n Cance l[RM B] th e Auto-Grab function. Th is w il l pl ace th e dupl icate d are a l igh tatth e e xact l ocation ofth e originalare a l igh t. In th e M ate rial /Lam p buttons ch ange th e l am p type

26

to Ph oton Lam p. In Bl e nde r onl y w ay to ge ne rate s caus tics in th e s ce ne is us ing th is l am p. Ch ange th e Ph oton s e ttings as in Fig. 2. Ste p7. Now s w itch ove r to Re nde r Buttons [F10] and ch ange th e s e s e ttings as in Fig. 3. Ste p8. Re nde r [F12] th e s ce ne ! Your re s ul ts s h oul d be s im il ar to firs tim age in pre vious page . Ifyour re nde r doe s n'tm atch ittry to m atch cl os e l y th e s e ttings as give n e arl ie r in th e figure s . You can al sol ook atth e e xam pl e caus tics .bl e nd fil e ifyou can'tfigure itout!

W O RK SH O P3D -

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Y afray caus tics s am pl e r tutorial

W h atJus tH appe ne d? Now th atw e h ave ge ne rate d a good e xam pl e ofCaus tics , now w e are going to l ook ath ow th e Caus tics w ork e d in th is s ce ne and w h at el s e options are avail abl e in th e bl e nde r inte rface . Th e re are th re e pane l s in bl e nde r inte rface th atcontain s e ttings for Caus tics : Th e firs tone is th e Yafray Pane lits e l f. Th is pane lal l ow s you to controlth e Yafray Re nde re r s e ttings . Norm al l y it's good e nough to jus tdis abl e XM Ls o th atyou can s e e th e inte ractive re nde ring. Al s o you can l e ave AutoAA e nabl e d to l e tYafray autom atical l y control th e anti al ias ing option. For de tail e d controlof Caus tics you w il lh ave to s w itch to m anualanti al ias ing s e tting th ough . Th e s e cond pane lis th e Yafray GI Pane l . GI s tands for Gl obalIl l um ination. Gl obal Il l um ination is th e e ffe ctproduce d by th e l igh t be ing e m itte d from a Gl oball igh ts ource . For th is e xpe rim e ntw e us e d th e Ful lType GI and s e tth e q ual ity to H igh for be tte r re s ul ts . O th e r s e ttings are De pth and CDe pth . De pth is th e dis tance th atYafray cal cul ate s a s ingl e ray during raytracing. Th e s m al l e r th e val ue th e q uick e r butl e s s accurate th e raytracing w il l be . CDe pth is s im il ar butitis for caus tics ph otons in th e s ce ne . Again th e s m al l e r th e val ue th e q uick e r butl e s s accurate th e caus tics in th e s ce ne w il lbe . W e al s o e nabl ed Ph otons in th is pane l . Th is w il le nabl e GI Ph otons w h ich are al s o re fe rre d to as H e l pe r

Ph otons . Th e y th e n are e m itte d from al lofth e l igh ts in th e s ce ne . Th e m ore ph otons (w e us e d 100,000) be tte r th e re s ul ts , butth is w il l al s o e xpone ntial l y incre as e th e re nde ring tim e . Th e l as tpane lis th e Lam p Pane l [F5]. Th is is l ocate d in th e M ate rial /Lam p buttons . You w il l ne e d to s e l e ctth e ph oton l am p in th e s ce ne to s e e th e Yafray Sh adow and Ph oton tab. By e nabl ing Ph oton Lam p w e e nabl e th e us e of ph otons for th e caus tics from a dire cts ource . H e re th e Pow e r s e tting is l ik e any oth e r l igh t and te l l s h ow "brigh t" th e caus tics w il lbe . Th is ph oton l am p al l ow s us to dire ctth e dire ction of caus tic and optim iz e th e caus tics re s ul ts nice l y. W e us e d about100,000 ph otons h e re . For s om e com pl e x s ce ne itcan go al lth e w ay up to a m il l ion! Itjus tde pe nds on h ow m uch com putation you w antto do! You can e xpe rim e ntw ith th e oth e r s e ttings as th e y us ual l y re q uire s om e te s ting butde faul t s e ttings w il lus ual l y ach ie ve good re s ul ts re gardl ess. Exte nding Caus tics Caus tics are notre s tricte d to Trans pare nt m ate rial s e ith e r! You can us e caus tics for m e tal l ic m ate rial s too, jus tre m e m be r th attw o m e tal l ic m ate rial s w il lal s o re fl e ctth e ph otons s o th e y ge ne ral l y w il lnots h ow up s om e tim e s . To finis h up th is tutorialI'l lgive you s om e s ugge s tions to pl ay around w ith :

Try adding a te xture or a col or to th e Cube and giving its om e Nor or Dis pl ace m e nt. Re pl ace th e Cube w ith a Sph e re or anoth e r m e s h . Us e s e ve ralPh oton Lam ps . H ave your s upe r cl us te r h andy! Us e an H DR Gl obal Te xture . Em ailm e your e xpe rim e nts ! I'd l ove to tak e a l ook atth e m !

I am a 17 ye ar ol d graph ics artis tand program m e r from San Antonio, Te xas . A fre e l ance s tudio artis tatID Studios [w w w .inte l l ide s ign.org] and a w e b program m e r atM ons te rW e b w w w .m ons te rw e b.ne t

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D PI de m y s tifie d

DPIde m ys tifie d You did it! You h ave trul y cre ate d a m as te rpie ce . Butw h e n you printe d itout, it l ook e d al lpixil ate d and bl ock y. Dang, you m us th ave a bad s e tting s om e w h e re . You go back , doubl e ch e ck al lyour s e ttings , h itre nde r again and w ait. Its til ll ook s th e s am e w h e n you printit. You s tartgl aring s il e ntth re ats at your printe r. W e l l , be fore you de cide to m ak e good on th os e th re ats , you m igh tw antto try one m ore th ing (your printe r w il lth ank you for it). You m ay h ave ove rl ook e d th e w h ol e DPI is s ue . W h il e it’s true th atBl e nde r h as s om e nice pre s e tre nde r s iz e s , ifyou don’t unde rs tand h ow th atre l ate s to printing, you w il lbe fore ve r gl aring atyour printe r. Firs tl e t’s l ook atw h atDPIactual l y is . DPI is a printing te rm th atde s cribe s th e num be r ofdots /pixe l s th atare de fine d in th e boundary ofa s q uare inch th atare us e d to cre ate an im age . Th e m ore corre ctte rm is pixe l s pe r inch , h ow e ve r dots pe r inch is ofte n us e d ins te ad (Th e im age can be a fontor graph ic). In ge ne ral , th e m ore dots , th e be tte r and s h arpe r th e im age . DPI is printe r re s ol ution. DPI is notim age re s ol ution al th ough fre q ue ntl y us e d th atw ay. O k , now th atw e k now w h atDPI is , l e t’s l ook at h ow itappl ie s to Bl e nde r. Bl e nde r re nde rs im age s outat72dpi, w h ich l ook s ok ay on your

s cre e n, butnot printe d out. In orde r for itto l ook good for print, you h ave to re nde r your im age bigge r and th e n re s iz e its m al l e r in your favorite graph ic program . Es s e ntial l y w h atyou w il lbe doing is s w apping ph ys ical dim e ns ions for re s ol ution. Tak e a l ook atth e fol l ow ing ch art(fig. 1 be l ow ). It s h ow s s om e com m on re nde r s iz e s in pixe l s and th e corre s ponding ph ys icals iz e s at72dpi (w h ich Bl e nde r us e s ) and a good printre s ol ution of 300dpi. You can s e e th atth e ph ys icals iz e s be com e s m al l e r as you incre as e th e re s ol ution. Th is m ay s e e m ove rl y com pl icate d, butre al l y itis not. Th e re is a ve ry s im pl e form ul a you can us e to ge tth e prope r s e ttings . Bas ical l y you m ul tipl y th e de s ire d re s ol ution by th e de s ire d ph ys ical s iz e to ge tth e pixe l s e ttings /s iz e you ne e d for Bl e nde r (fig. 2).

O nce you h ave re nde re d your im age us ing th os e s e ttings , you ne e d to go into your favorite im age program and re s iz e your im age . M os tim age program s w ork s im il arl y, s o figuring itoutin your program s h oul dn’tbe difficul t. I w il lbe us ing Ph otos h op to e xpl ain th is part, be caus e th atis w h atI h ave .

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D PI de m y s tifie d

Ste p 1: O pe n your im age Ste p 2: Go to Im age >Im age Siz e , a dial og box l ik e fig. 3 s h oul d ope n. Ste p 3: Atth e bottom ofth e box, unch e ck “Re s am pl e Im age ” Ste p 4: Ne xtl ocate th e “Re s ol ution Box”, e nte r your ne w re s ol ution. Th e W idth and H e igh tboxe s s h oul d autom atical l y update to re fl e ctth e ne w s iz e atth atre s ol ution.

O k ay, s o now you h ave a be tte r unde rs tanding ofdpi and h ow to ge tth e prope r dpi for printing, butw h atdpi re s ol ution is be s tfor w h atyou ne e d. As a ge ne ralrul e , you s h oul d ch oos e a re s ol ution be tw e e n 150-300 dpi. Th is re s ol ution is good for m os tprintproje cts . Ifyou are h aving s om e th ing profe s s ional l y printe d, itis al w ays a good ide a to ch e ck w ith your printe r and find outw h atre s ol ution th e ir e q uipm e ntruns at.

Ste p 5: H itth e “O K ” button and s ave , you are al ldone and now your im age w il lprintl ik e you e xpe cte d itto.

H i, m y nam e is Sandra Gil be rt, (ak a dre am s gate ). I h ave be e n us ing bl e nde r for a l ittl e ove r five ye ars . I curre ntl yl ive in Nam pa, Idah o, USA and w ork as a graph ic de s igne r for a s m al lprints h op. I’m m arrie d and h ave 2 ch il dre n, w h ich l e ave s notne ar e nough tim e for fe e ding m y grow ing bl e nde r obs e s s ion. Ye t s om e h ow I al w ays m anage to find th e tim e to e xpl ore ne w fe ature s , k e e p up on th e l ate s tne w s and s tartne w bl e nde r proje cts . Som e ofth e m I actual l y e ve n m anage to finis h .

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Book Re vie w

DigitalLigh ting and Re nde ring Th is is s ue w e are re vie w ing “[digital ] Ligh ting and Re nde ring” by Je re m y Birn. By now w e h ave al lfigure d out, or s oon w il l , th at l igh ting is a ve ry l arge partofany s ucce s s ful proje ct. You can h ave th e be s tm ode l s, m ate rial s and com pos ition, butw ith outprope r l igh ting your im age w il lfal lfl at. Ente r “[digital ] Ligh ting and Re nde ring”. Je re m y Birn tak e s you s te p by s te p, w ith l ogicaland cl e arl y e xpl aine d e xam pl e s , th rough th e ofte n com pl e x and confus ing are a ofl igh ting. H e s tarts you offw ith h ow to s e tup a good l igh t w ork fl ow and th e n e xpl ains e ach type ofl igh t you s h oul d h ave avail abl e. H e continue s w ith in-de pth dis cus s ions on w h at l igh ting is and h ow l igh tand s h adow be h ave in th e re alw orl d, th e n progre s s e s th rough col or th e ory, q ual ity ofl igh tand s h adow and e xpos ure . No book on l igh ting w oul d be any good w ith out a th orough dis cus s ion ofl igh ts e tups . And th is one is an e xce l l e ntre s ource for l e arning about th e various l igh ts e tups and th e ir us e s . H e goe s on to e xpl ain h ow m ate rial s fitinto th e re nde ring pipe l ine . Starting w ith s h ading s urface s , h e w ork s h is w ay th rough de tail ed e xpl anations ofh ow diffe re ntm ate rials e tups

affe ctl igh ting and re nde ring. In th is s am e ch apte r h e al s o e xpl ains th e us e s and advantage s ofraytracing and gl obalil l um ination. Th e finalch apte r cove rs com pos iting and re nde ring in l aye rs , s h ow ing th e us e ofdiffe re nt re nde r pas s e s to ge tjus tth e e ffe ctyou are l ook ing for. Th is book is a de finite “m us tre ad” for be ginne rs and ye te ve n an e xpe rie nce d CG artis tw il lfind itw orth a l ook . --bl e nde rart

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H el l o! de ar bl e nde r h e ads . W e h ave be e n bringing forth a bundl e ofgood l e arning m ate rialfor you for th e pas ts ix m onth s . In e ve ry is s ue , w e tak e on a particul ar as pe ctofCG re l ate d to Bl e nde r and pre s e nt you w ith a pack ofus e full e arning m ate rial . Al l th is is m anage d w ith th e h e l p ofth e e xpe rie nce d bl e nde r h e ads from w ith in th e bl e nde r com m unity. Th e y h e l p s pre ad th e k now l e dge by s h aring conte ntfrom th e ir re s pe ctive fie l d ofe xpe rtis e . Back w h e n w e jus ts tarte d th e m agaz ine , it w as our aim to provide a good re s ource to cove r th e diffe re ntas pe cts ofCG w ith th e m ain focus be ing on th e e as e ofl e arning for th e ne w us e rs . W e h ave be e n ove rw h e l med by th e cons tantapprais aland fe e dback w e got from th e bl e nde r com m unity. Th ats h ow s th at w e h ave atl e as tbe e n s ucce s s fulin th atare a. I tak e th is opportunity on be h al fofour s m al l te am atbl e nde rartto th ank you al lfor your com m e nts and fe e dback and attim e s , patie nce . And al s o to th e fol k s w h o h ave provide d m uch ne e de d m ate rialfor th e m agaz ine .

Th is tim e w e gotour w e bs ite h os te d th ank s to ibibl io.org w h ich gracious l y provide d us w ith th e w e b s pace . Nam Ph am did a gre atjob w ith th e ne w w e bs ite de s ign and h e h as al so provide d th e l ong w ante d s ol ution for s ubs cribing to our m ail ing l is t. Now al lth os e w h o w il ls ubs cribe to itw il lge tnotifie d as s oon as th e ne w is s ue is l aunch e d. W ith th is is s ue outw e are al s o s tarting to re s tructure both th e m agaz ine de s ign and th e conte nts s o th atw e can continue to provide you al lw ith e ve n be tte r l e arning e xpe rie nce for th e tim e to com e . So untilth e n do k e e p s e nding us your val uabl e fe e dback and com m e nts . H appy bl e nding! Gaurav gaurav@ bl e nde rart.org

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