Scripting - ExtrudeCrv ToBoundary

Scripting
1

I’m wondering if it is possible in any way to script the ToBoundary function of ExtrudeCrv.

The only topic about this I could find was this one where the best solution seems to be call rs.Command() with a ExtrudeCrv command. This is rather clunky and I’m curious if people know of a more elegant solution to use the ToBoundary option or at least emulate the behaviour of the ToBoundary option?

2

Oh, I’m sure it’s possible without scripting the Rhino command. A quick “script logic” might be this:

  • Choose the curve or surface to extrude
  • Choose the boundary surface
  • Get a global bounding box for the two and concoct some distance that will ensure that when extruded, the extrusion goes past the boundary
  • Extrude
  • Intersect the extrusion and the boundary surface as a check
  • If it is successful, check surface normal of the boundary surface and flip if necessary
  • Use Brep.CreateBooleanDifference to subtract the boundary surface from the extrusion.
  • Along the way, various checks for validity, etc.
3

Would BooleanDifference work if neither of the surfaces are closed? :sweat_smile:

If not, I might have to rethink my plan. The boundingbox check is a very good point!

Could also go for an intersect -> if closecrv

4

I think it should, but haven’t tried. There is no remark in the api doc that says that it is limited to closed volumes, just this:

The solid orientation of the breps make a difference when calling this function

Which leads me to believe that it will work on open stuff…

5

I just realised that my description of “not closed” is open for interpretation.

Example
Example.png551×771 33.2 KB

6

sigh

Funny how you can be stuck on something for a long time and then as soon as you ask it, you find the solution.

Extrude airfoil past boundary
Boolean Difference -> Boundary -> Airfoil
Result (only necessary check is check for surface normals, but that’s already taken care of):

image

Optional Explode to separate surfaces

7

Yep, essentially the script logic above does what you can do manually with Rhino commands…

8

With the added bonus of looping through countless combinations of input parameters to create a geometryset for simulations. It would drive me mad to do that all myself haha