What's New Autocad 2010_segment_1

ATP244 What’s new in AutoCAD 2010 Segment 1

Date: April 6, 2009 Instructor: Kenneth Leary Level: All Levels Category: AutoCAD 2010

Web: www.AUGI.com

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Introduction It’s April, the flowers are blooming, birds are chirping, and spring is in the air. It must be time for the next version of AutoCAD to be released. This year, the good folks at Autodesk have done their best to put together another version that tempts the wallets of even the stingiest user. I don’t know how many of you are Star Trek fans, but there has always been a belief among many of the fans that the even numbered movies were better than the odd numbered ones. I’ve yet to meet a person that would pick Star Trek V: The Final Frontier as their favorite over the very popular Star Trek II: The Wrath of Khan. I’m not asking everyone to don some Spock ears and speak Klingon with me, I’m simply illustrating the point because, oddly enough, that same theory seems to hold true with AutoCAD. There’s no comparison between Release 13 and the much-lauded Release 14. Some old school AutoCAD users like myself still long for the heady days of Release 12. Well, AutoDesk has done nothing to prove the even number theory wrong. AutoCAD 2009 made huge changes in the user interface, with the introduction of the menu ribbon and a completely revised the look and feel of the program. It was also slower, a memory hog and had more than it’s share of glitches. Once again, the even numbered release has a lot great new commands and time saving tools to offer and it’s a more stable program to boot. In this course, we’re going to cover the new commands, the improved commands, and the ones that have been completely over hauled.

Parametric modeling The biggest and initially the most intimidating new feature in AutoCAD 2010 is Parametric Modeling. You may be surprised to find that there is no actual Parametric command. That’s because it’s the name for a new set of tools that allow you to create geometric relationships between objects or restrict the dimensional properties of objects. The two different types of tools are referred to as geometric and dimensional constraints. That doesn’t sound that complicated now does it? Well before you panic and pull out the old dictionary that you used to use to decipher what Dennis Miller said on Monday night football, relax. We’ll go through the tools and their usage in plain English and before you know it, you’ll see that it’s really not complicated at all.

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All of the constraint settings and display options are handled by the Constraint settings dialog box. You can open it with the CONSTRAINTSETTINGS command. We’ll refer back to this command as we cover the different constraint functions and commands. Another important feature that is used with the constraints are the Constraint Bars, these show which constraints are applied to drawing objects. The CONSTRAINTBAR command effects how the constraint bars are displayed. When constraint bars are displayed, you can pass the cursor over a constraint to view the constraint name and the objects that it affects. You can also control the display of constraint bars with this command or use the Show, Show All, and Hide All options on the Geometric panel of the Parametric ribbon tab.

There is a new Tab on the menu ribbon for the parametric modeling tools called the Parametric tab. This tab is broken down into three panels, each with a different set of tools that you would use for the different constraint functions. Let’s look at each separately.

Geometric Constraints The first panel on the left side of the Parametric tab is for the tools that create and modify geometric constraints. These are the relationships that are applied between two objects, points on objects, or between a single object and the coordinate system. In simple terms it works like an object snap that stays persistent throughout your design. The middle sub panel on the Geometric constraints panel contains the commands that you will use to apply the constraints to objects in your drawings. These can be accessed from this location on the ribbon or with the GEOMCONSTRAINT command. There are twelve to choose from, we’ll cover each of them. Coincident - Constrains two points on two objects together. A constraint point on an object can be made coincident with an object or a constraint point on another object. When the cursor hovers over the constrained point, the constraint bar to the right is shown.

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Colinear – Constrains two or more line segments to lie along the same line. Regardless of how the original line is moved or rotated, the Colinear line will move to match the new location.

Concentric - Constrains two circles to the same center point. This also works for arcs and ellipses. The result is the same as that of a coincident constraint applied to the center points of the curves. Moving one of the circles will move the other with it, much like a block.

Fix - Locks a point or curve in position. The fixed point can be on an object, or a point in relation to an object, like a center point of a circle for example. This command may be a let down for those people who thought it might fix something in the drawings that doesn’t seem to work the way they wanted it to.

Parallel – Constrains two lines or polylines to be Parallel to each other. When one is modified the other will move to match it.

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Perpendicular - Causes selected lines to lie 90 degrees to one another. Perpendicular constraints are applied between two objects and, unlike the Perpendicular object snap, these lines do not have to be touching each other when the constraint is created.

Horizontal - Causes lines or pairs of points to lie parallel to the X axis of the current coordinate system. Be aware when using this constraint that they are set to the axis in the coordinate system in which they were created. When another user coordinate system is active the Constraint bar icon (pictured below) will change to show that the current axis in not the one that the constraint was created in.

Vertical - Causes lines or pairs of points to lie parallel to the Y axis of the current coordinate system. Just like the Horizontal constrain these are set to the axis in the coordinate system in which they were created. When another user coordinate system is active the Constraint bar icon (pictured on the right) will change to show that the current axis in not the one that the constraint was created in.

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Tangent - Constrains two objects to maintain a point of tangency to each other or their extensions. Tangent constraints are applied between two objects, those objects could be a curve (arc or circle) and a line or another curve. A circle can be made tangent to a line even if the circle does not touch the line and a curve can be tangent to another even if they do not physically share a point.

Smooth (G2) - Constrains a Spline to be contiguous and maintain continuity with another spline, line, arc, or polyline. When the constraint is applied the endpoints of the curves to which you apply the smooth constraints are made coincident.

When two Splines are selected, they are updated to be contiguous with one another. This function is similar to using the JOIN command for polylines except the splines are not joined to be one object; they only behave as if they were one object.

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Symmetric - Causes selected objects to become symmetrically constrained about a selected line. The function is similar to that of the Mirror command. Unlike other constraints where two objects are selected, with a symmetric constraint you must have an axis around which you will constrain the objects or points to be symmetrical.

This is referred to as the symmetry line. For lines, the line’s angle is made symmetric and not the endpoints. For arcs and circles, the center and radius are made symmetric not the endpoints of the arc.

Equal - Resizes selected arcs and circles to the same radius, or selected lines to the same length.

Constraint Settings The sub panel on the far right side of the Geometric panel controls the display of the Constraint Bars. This is where you can control the display of constraint bars with the Show, Show All, and Hide All options. These are the same functions that are available in the CONSTRAINTBAR command mentioned earlier. Show will display the current constraints that apply to an object when you place your cursor over the object. It will also highlight the objects affected by the constraints. Show All will turn on all the constraint bars for the objects in the drawing that have constraints applied to them. Hide all turns off all of the constraint bars in the drawing.

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Auto Constraints The sub panel on the left contains the AutoConstraint command. This tool can significantly speed up the process of adding constraints to objects. AutoConstraint will add specific constraints to objects that meet certain parameters. For example, applying AutoConstrain to two circles will apply the appropriate concentric constraint while applying AutoConstraint to a rectangle applies the coincident, horizontal, parallel, and perpendicular constraints to maintain the rectangular shape. Which constraints are applied automatically can be preset in the constraint settings dialog box. Select the button on the menu panel or type in CONSTRAINTSETTINGS at the command prompt and select the AutoConstraint tab.

This dialog will allow you turn determine which constraints are applied to an object or a selection set and also gives you the ability to change the order in which the constraints are applied. There are also toggle buttons that can be used to require that a tangent constraint will only be applied if the arc and the tangent object share a common point or if two perpendicular lines intersect before the constraint will be applied. Distance and angle tolerances can be applied to limit the tolerances that are applied to those values.

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Dimensional Constraints Dimensional constraints function much like associative dimensions, only in this case it’s the object that changes to match the dimension and the not the dimension changing to match the object. Dimensional constraints have a panel on the Parametric tab next to the Geometric constraints. This panel contains several commands, which will apply different dimensional constraints. Linear – Linear constraints create a horizontal or vertical dimensional constraint. Select the Linear icon on the Dimensional constraint panel or type DIMCONSTRAINT and select the Linear option Selecting the pulldown menu on the lower half of the icon allows you to choose from Linear, horizontal or vertical. Linear switches from vertical to horizontal dynamically depending on the direction that you move the dimension line based on the extension line origins.

Horizontal places horizontal constraint, regardless of the angle of the object and Vertical does the same in the vertical direction. When a new dimensional constraint is created it is given a unique identifier by AutoCAD. These identifiers can be changed in the parameter manager, which we’ll cover later. Aligned – Aligned dimensional constraints are much like the aligned dimensions in that they align with the angle of the object that they constrain. Select the aligned icon on the Dimensional constraint panel or type DIMCONSTRAINT and select the Aligned option. At the command prompt the options Object, Point & line, and 2Lines appear. Object will allow you to add the aligned constraint to an object without picking constraint points. Point & line will select a constraint point and the closest point on a line to that point. 2lines is handy in that it will select two lines and make the second parallel to the first and maintain the distance between the two lines.

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Radial – This is not a constraint that involves tires, it controls the radius of an arc or circle. Diameter – Like the Radial constraint, this constrains the diameter of an arc or a circle.

Angular – Angular constraints control the angle between two line or polyline segments, the angle swept out by an arc or a polyline arc segment, or the angle between three points on different objects. If the angle is greater than 360 degrees or is a negative number, the number displayed is based on the units in the drawing. For example, in decimal degrees, 390 degrees would display as a 30-degree angle. Form – This constrain commands serves two purposes, first it will convert associative dimensions into a constraint or it can specify whether a constraint it dynamic or annotational. These will most likely raise two questions, why is it called Form and not Convert and what are dynamic or annotational constraints? There is one answer for both questions, although it’s a complicated answer. There are three forms of dimensional constraints; dynamic, annotational and reference. This command determines which “form” the Dimensional constraint will take on. Let’s look further into what purpose the three forms of constraints server.

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Dynamic constraints are the default form of dimensional constraints. These are best for normal parametric drawing and design tasks as they function much like a construction line would. They can easily be turned on or off globally in the drawing using the DYNCONSTRAINTDISPLAY command. They display using a fixed, predefined dimension style. They position the text information of the constraint automatically, and provide triangle grips with which you can change the value of a dimensional constraint and they do not display when the drawing is plotted. Annotational constraints are useful when you want dimensional constraints to have more of the characteristics of typical dimensions. They can be placed on layers, which is not an option available to Dynamic constraints. They are displayed using the current dimension style. They can be modified using grips provide grips similar to those used on dimensions. They are also displayed when the drawing is plotted. After plotting, you can use the Properties palette to convert annotational constraints back to dynamic constraints. Reference constraints are driven by the geometry and are strictly for informational purposes. This means that it does not control the associated geometry, but rather reports a measurement similar to a dimension object. Dynamic and Annotational Constraints can both be converted into reference constraints. Reference constraints will always display the text information in parentheses and cannot be modified. Like an associative dimension, it will follow the constrained geometry and display the new information for that object or objects.

Managing Constraints The final panel on the Parametric menu tab is the Manage panel. This panel has only two commands, Delete constraints and the Parameters manager. A constraint can be deleted at any time by simply selecting the individual constraint and selecting ERASE or hitting the delete key. Delete constraints will delete all of the constraints associated with the selected object at one time.

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The Parameters Manager is a palette that displays the constraints in a drawing and all of the associative variables (dimensional constraint variables and user-defined variables). The Parameters Manager palette displays three columns, by default. You can also right click and use the shortcut menu to add two columns for Description and Type. The Name column displays the name that AutoCAD generated for the dimensional constraint. This name can be changed to something more user friendly. The Expression column displays the real number or the equation for the expression, for example, d1+d2 or 390 degrees. The Value column shows the number that will be displayed on the dimensional constraint. For example, it would show the distance between d1+d2 or 30 degrees. Description and Type, if displayed, will show user comments added to the constraints and dimensional constraint type respectively.

Conclusion of Segment 1 Hopefully this segment helped clear up the mystery behind Parametric modeling. While it all may seem intimidating, after experimenting with it you might be surprised at how easy it is to use the new commands. In the next segment we’ll look at some more new commands and some of the ones that have been completely overhauled. Remember that this material is only a portion of the class, support is always available online in the private course forum. I encourage you to visit the course forum and ask any questions that you may have about this segment or simply join in the discussion. The ATP Mantra is: the only stupid question is the one you don’t ask. Thanks again for attending this course!

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