Blender Tutorial

90 minutes of fun with Blender

Tutorial Christian Lipski Computer Graphics Lab TU Braunschweig

Acknoledgement: Some parts of this tutorial have been “inspired by” the original blender tutorials from the blender wiki at http://wiki.blender.org/index.php/Manual. I suggest giving the online manual tutorial a try if you get stuck at some point. During this first tutorial you will learn some blender interface basics, and you will learn how to create your first blender 3D model, including texturing. We will not cover animation, lighting and rendering, as these parts are not necessarily needed for basic modeling. At first, let's get started with the user interface of blender The interface can be broken down into several key areas: Windows, Contexts, Panels, and Buttons (controls). For example, The Button window contains Context buttons which show different groups of Panels and the Panels each show groups of Buttons.

Mouse Button Emulation It is perfectly possible to use Blender with an Apple single-button Mouse. The missing buttons can be emulated with key/mousebutton combos. Activate this functionality in the User Preferences, View and Controls Context, Emulate 3 Button Mouse button. The following table shows the combos used:

3-button Mouse

Apple Mouse

MMB

Option/Alt key + mouse button

RMB

Command/Apple Key + mouse button

All the Mouse/Keyboard combinations mentioned in the Tutorial can be expressed with the combos shown in the table. For Example, ShiftAlt RMB becomes ShiftAltCommand LMB on a singlebutton mouse.

The Window System When you start Blender you may see a console (text) window open and, shortly after, the main user interface window will display. You may also see a splash screen announcing the Blender version, but it will disappear as soon as you move your mouse. .

The default Blender scene. The default Blender scene shows the screen you should get after starting Blender for the first time. By default it is separated into three windows: • •

The main menu at the top is the header part of a User Preferences window A large 3D window (3D Viewport window)

•

The Buttons Window (at the bottom)

If you want to rearrange your interface by adding or removing windows, click RMB or MMB on the border of two windows: Using the Split menu you can resize windows by dragging their borders with LMB . You can join two windows into one by clicking a border between two windows with MMB or RMB and choosing Join Areas. Then you'll be prompted to click on one of the two windows; the one you click will disappear, while the other will be expanded to cover the full area of both windows. If you press Esc before clicking on one of the windows, the operation will be aborted.

Window types The window type selection menu. The Blender interface, the rectangular window provided by your operating system, is divided up into many rectangular window frames. Each window frame may contain different types of information, depending upon the Window type. For, now, we will need the following window types Window types are broken up by functionality: • • • • •

File Browser - for storage and retrieval, especially of .blend files Image Browser - search your computer for images, seen as thumbnails Buttons Window - panels that configure objects and set/select options UV/Image Editor - edition of the UVmaps ; edit and paint pictures 3D View - graphical view of your scene

Screens Layout dropdown Blender's flexibility with windows lets you create customized working environments for different tasks, such as modeling, animating, and scripting. To do each of these major creative steps, Blender has a set of pre-defined screens, or window layouts, that show you the types of windows you need to get the job done quickly and efficiently, for now, we'll just need the model screen.

Contexts The Button Window shows six main Contexts, which can be chosen via the first icon row in the header (Contexts and Sub-Contexts Example). Each of these might be subdivided into a variable number of sub-contexts, which can be chosen via the second icon row in the header (Contexts and Sub-Contexts Example), or cycled through by pressing the same Context button again. The context you will most probably use today are printed in bold letters • • •

•

• •

Logic (F4) - Switches to Logic context. Script - No shortcut. Switches to Script context. Shading (F5) - Switches to Shading context. • Lamp - No shortcut. • Material - No shortcut. • Texture - Shortcut F6. • Radiosity - No shortcut. • World - Shortcut F8. Object (F7) - Switches to Object context. • Object - No shortcut. • Physics - No shortcut. Editing (F9) - Switches to Editing context. Scene (F10) - Switches to Scene context. • Rendering - No shortcut. • Anim/Playback - No shortcut. • Sound - No shortcut.

Your First Model in 60 minutes This chapter will guide you through the creation of a small "Domo-kun” character. In Part I of this tutorial we'll build a the geometry. Then, in Part II, we will create a UV map and add texture. When starting Blender, you'll be confronted with a scene containing a light, a camera and a cube. At first, try to navigate through the scene with the keys on the numpad. 8 4 6 and 2 let you rotate the rotate around the scene CTRL+8 CTRL+2 CTRL+6 CTRL+4 let you move around the scene + and - let you zoom in and out 7 switches to a top view of the scene 1 switches to a front view 3 switches to a side view 5 toggles between perspective and ortographic mode 0 switches to the view of the camera (everything inside the rectangle will be rendered, eventually) The first concept in editing is that you can switch between object and edit mode: Edit Mode and Object Mode Edit Mode is a mode in which you can edit the vertices of the mesh. By default, all vertices are selected for every new object created (selected vertices are highlighted in yellow - unselected vertices are pink). In Object Mode, vertices cannot be selected or individually edited; the object can be changed only as a whole. You can press TAB to switch between these two modes, and the current mode is indicated in the header of the 3D window. As we will only work on a single model for now, we will be in edit mode view most of the time. The cube is in general a good geometric primitive to start off with. But before we get any work done, we should import Templates of the models we want to build. In the 3D view window, click View->Background Image A little window will appear, there click Use Background image the click Load and select the image domo_front.jpg Important! You will only see the background image if you are in orthographic projection (use 5 on keypad to switch between modes) and if you either pressed 7, 1 or 3

Press 1 to get to the front view. Now you should see something like this:

We can now start working on the actual model. Make sure you're in Edit Mode (toggle between modes with Tab).

When editing a mesh, you can either edit vertices, edges or faces. To switch between these types, click on the appropriate icons: There are several ways to specifiy a selection: RMB Select a single element (previous selection is discarded) Shift+RMB add / remove an element from selection B + drag LMB add all elements within a user specified box

Illustration 1: vertex, edge and face select

After selecting a single or multiple elements of the objects you can move them by dragging the coloured axes or press r or s to rotate / scale them (this may only make sense when multiple elements are selected). Click LMB to accept the current transformation, click RMB to abort the operation. HINT: if you specifically know what you want to do, you can type in numerical values while performing a transformation, e.g. type in 45 followed by enter while rotating vertices and they will be rotated by exactly 45 degrees. You can also constrain operations to a single axis by typing x, y or z during an operation. For now, you can only modify the eight vertices of the box, you will have to refine the geometry so it looks like Domo-kun in the end. I suggest two ways of refining geometry: If you want to extend the geometry to a direction, select (at least) a face, got to the editing panel (F9) and click Extrude under Mesh Tools. Now you can extend the face along the normal direction. Press

LMB to accept the extension or RMB to abort. If you want to add geometric detail, simply select a number of faces and click Subdivide under Mesh Tools.

Illustration 2: Suggested Methods for mesh refinement ind Edit Mode (1): Extrude (2), Subdivide (3) and Remove Double (4) that can be modified by Limit (5) Hint: Depending on which selection mode you use (RMB or Box select), you will select only elements visible on your side of the object or also on the other side. Hint: You may also want to try modeling symmetric models with a special trick (although I rather dislike it myself). See the online tutorial for details: http://wiki.blender.org/index.php/Manual/Your_First_Animation_in_30_plus_30_Minutes_Part_I After experementing with the controls and changing the viewpoint from time to time, you hill have something like this:

This might look nice from the front, but when you move around it looks pretty ugly:

Go to the side view (press 3 ) and load the domo_side.jpg background image. Now you can modify the mesh so that it looks good from both views. At last, switch do different 3D viewing angles and modify the model so that it looks like you imagine it.

This is the level of detail we should be happy with for now. We still have the arms, the eyes and the label to model. Instead of refining geometry, I'll just add more basic shapes (e.g. cubes) by clicking Add->Mesh->Cube Make sure you are in Edit Mode while doing this. Otherwise, you will end up creating a new object instead of adding geometry to your existing model. You will realize that the cube works fine as a basic primitive for most objects, but for some types of geometry, other primitives may be more suitable (e.g. a sphere when modeling an eye). In order to copy parts of your mesh, select them and press Shift+D. You may also press m followed by x,y or z in order to mirror parts along the specified axis. After adding the arms, the eyes and a little detail for the mouth, the the model looks like a lot nicer. When creating the eyes, I added an icosphere for each eye and deleted the invisible parts of it by selecting all vertices and pressing DEL. You'll soon see why...

We're done with the modeling for now, let's get started with the texturing

UV Mapping UV mapping or UV unwrapping is basically a step that can be done automatically by an algorithm. All that needs to be done is to find a projection for every 3D face of an object to a 2D texture space. In many modeling tools, that space is also known as UV space. My experience is that although automatic unwrapping works quite well in many cases, some user interaction can improve the quality of the unwrapped model and can therefore save a lot of time when actually drawing the texture. For our example, we'll already have a texture so that we have to align the UV unwrap to this texture. Blender offers a very intuitive way of semi-automatically unwrapping. You can define seams on an objects that separate different surface patches, just like on a plush toy. Since we're actually modeling a plush toy, we'll stick to the seams that can be found on the model. At first, select all edges that are located on one of Domo's seams:

The seams partition the torso of Domo into seven main parts: A huge part covering his face and his back (1), two patches covering each side (2, 3) and two patches covering his legs (4, 5). the two last pacthes cover his feet and cannot be seen in the above figure. Important! Make sure that you do not miss an edge and that all patches can be easily unwrapped to a surface without much distortion. We click Mesh->Edges->Mark Seams . The coloured lines along the edges will become broader. Repeat the same procedure for the arms, dividing each arm into an upper and a lower patch. Because the eyes can be easily unwrapped (we erased points on the back, so they can easily be flattened), we do not have to mark seams there. We split the 3D window (click with MMB or RMB on the border of two windows and select split view, click LMB to define where the split is applied) and select UV/Image Editor as the window type. In the 3D View, we select all faces in edit mode and click Mesh->UV Unwrap In the following dialog, we select Unwrap. If all edges were correctly marked as seams, the result should look somehow like this:

On the left we can see (with some imagination) all 13 patches we separated earlier flattened out on the UV space. Similar to editing vertices in 3D space, you can select UV vertices with RMB, B+LMB and a . Click and drag LMB to move vertices or press r to rotate them. Another useful hotkey is w that lets you align vertices along an axis or weld them to a single point. If you want to select all vertices belonging to a patch, select one and press CTRL+L. Load the texture domo_tex.jpg by clicking Image->Open. Now try to align the UV mapping with the texture. Please note that multiple patches (I.e. the sides, the eyes, the arms and the feet) may be mapped to the same UV coordinates in order to save texture space. In the end, domo should look like this:

Hint: You may want to refine your mesh so that the model's shape looks smoother. I suggest to use Mesh Tools->Subdivide and Mesh Tools->Smooth to achieve this effect. You may also want to use normal interpolation. In Editing Mode (F9), select all faces that should look smooth and click Link And materials->Set Smooth Basically, now you have all things needed to export the mesh to an .obj file readable by your ray tracer. Goto File->Export->Wavefront(.obj) You can go on and have fun with Blender. Here are some neat things to do: -Get to know Blender Materials and assign a proper material to your model (the texture used in this tutorial was only used to align the UV mapping, actual materials are a little more complex) -Play around with lighting and camera and render some nice pictures -Add skeletal animation to Domo and make him walk -Add more characters, background objects, a compelling story and produce your own award-winning film