Thursday, May 29, 2008

Sketch Constraints

In the last post I discussed some of the initial 2D sketching capabilities of Wildcat CAD. In this post I will expand on that a bit and talk about the dimensional and geometric constraints that can be added to 2D sketches. Here is a quick status on all of the planned constraints:

Dimensional Constraints
  • Length
  • Angle
  • Distance (works for some features but not all)
  • Radius
Geometric Constraints
  • Fix
  • Coincidence (line-line only as of now)
  • Horizontal
  • Vertical
To Be Implemented Constraints
  • Semi-major & semi-minor axis
  • Concentric
  • Tangent
  • Parallel
  • Midpoint
  • Perpendicular
  • Symmetric
  • Equidistant point
In the picture below you can see a selection of these constraints:

Where the lines of the rectangle meet (created using the Rectangle profile tool), you can see small points. These are the coincidence constraints.  Next to mostly horizontal or vertical lines you can see the appropriate constraint.  I created an angle constraint between the two lines in the upper left corner.  Both the arc and the circle have radius constraints.

It is important to note that as of right now these constraints are not being using to properly constrain the sketch.  It is our goal to move in that direction in the near future, but for now the constraints are just visual objects.

If you move the lines or edit the arc and circle, you should see the dimensional constraints change value.  If you change a line from vertical to not vertical, the vertical constraint will not go away.  This concept applies to all geometric constraints for now.

As with all other sketch features, constraints created in a sketch are show in the specification tree when in 3D mode.

Tomorrow I will add some more detail about editing sketches.

P.S.  In addition to adding comments to this blog, you can also visit the Wildcat CAD discussion group. 

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