AutoCAD® 2010

Tips and tricks


Parametric Drawing
Powerful new parametric drawing functionality in AutoCAD 2010 enables you to dramatically increase productivity by constraining drawing objects based on design intent. Geometric and dimensional constraints help ensure that specific relationships and measurements remain persistent even as objects are modified.The tools for creating and managing geometric and dimensional constraints are available on the Parametric ribbon tab, which is automatically displayed in the 2D Drafting and Annotation workspace.

Figure 1. Parametric ribbon tab

Establishing Geometric Relationships
Geometric constraints establish and maintain geometric relationships between objects, key points on objects, or between anobject and the coordinate system. Pairs of key points on or between objects can also be constrained to be vertical or horizontal relative to the current coordinate system. For example, you could specify that two circles must always be concentric, that two lines are always parallel, or that one side of a rectangle is always horizontal. Applying Geometric Constraints Geometric relationships are definedwith geometric constraints, located on the Geometric Panel of the Parametric tab of the ribbon, or with the GEOMCONSTRAINT command. When applying constraints, an icon appears next to the cursor to help you remember which constraint you selected.

Figure 2. Concentric geometric constraint icon
When applying a constraint to points, a temporary marker identifies the closest valid point whenrolling over an object. It generally corresponds with points that can be used as object snaps. Whether selecting objects or points on objects to constrain, the order and pick location affects how the objects update: the second object selected updates to satisfy the constraint. After the constraint is applied, though, either object will update when the other is modified.

Figure 3. Applying a parallelconstraint



Figure 4. Applying a coincident constraint

Figure 5. Applying a concentric constraint

AutoConstrain You can significantly automate the process of applying constraints using the AutoConstrain functionality, available on the Geometric panel of the Parametric tab. AutoConstrain automatically applies constraints to geometry that falls withinspecified tolerances. For example, applying AutoConstrain to a rectangle consisting of four lines generates the appropriate coincident, horizontal, parallel, and perpendicular constraints to maintain the rectangular shape through various edits. You can control which constraints are available, in what order they are applied, and a tolerance to determine whether constraints are automatically applied.These controls are available on the AutoConstrain tab of the Constraint Settings dialog box, which you can access from the Parametric tab or using the CONSTRAINTSETTINGS command.

Figure 6. Access to Constraint Settings dialog box



Figure 7. Constraint Settings dialog box, AutoConstrain tab
Constraint Bars Constraint bars show the constraints applied toan object. You can control the display of constraint bars using the CONSTRAINTBAR command or the Show, Show All, and Hide All options on the Geometric panel of the Parametric ribbon tab. When constraint bars are displayed, you can pass the cursor over a constraint to view the constraint name and the objects that it affects.

Figure 8. Constraint bar



Youcan further control the display of constraint bars on the Geometric tab of the Constraint Settings dialog box. Options include the ability to individually specify which types of constraints can be displayed in the constraint bar, apply transparency, and automatically show the constraint bars after applying constraints to selected objects regardless of the current constraint bar visibility setting….