Fast 2D Curve Booleans in Ordinary Rhino Workflows

Rhino Rhino for Windows
1

I’d like to boolean two sets of complex curves. All curves are closed, disjoint, non self-intersecting, and co-planar. But there can be dozens of them. Is there a fast and automatic way to do this outside of grasshopper?

So far I’ve:

  • developed a workaround using extrusions and solid boolean operations, but haven’t turned it into a script yet.
  • I’ve found Clipper’s BooleanPolyline function - this showcases the functionality I’d like to have, but lacks full nurbs curve support.

Current Practice

For boolean union I can use _curveboolean _pause _allregions.

For boolean difference I do:

  1. Use _ExtrudeCrv _Solid=yes with distance 1 for set A, and 0.5 for set B. Creates two sets A’ and B’ of solids.*
  2. Use _BooleanDifference to create a set of solids C’ = A’ - B’.
  3. Create plane P in the construction plane, containing the projection o C’
  4. _Intersect P and C’. Gives result C = A - B.

Intersection is similar.

image
image.png939×751 255 KB

I think the intermediate shape is rather fun! However I’d like to make the technique less manual. This message is to check if it’s already done. Thanks!

*) I use a 0.5 extrusion height for B’ in order to avoid the boolean difference failed error, which happens if any solid in B’ fully contains some solid in A’.

2

Should be quite easy in Python You could even make it so you don’t even need to select your objects if they are sorted on the right layers.

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Thanks @siemen! As always @Helvetosaur is a hero!

I’m working on adding support for internal holes in the profile sets, based on Helvetosaur’s code. I will publish the code when it’s done.