I’ve created a definition that takes a polyhedron that’s been trimmed with planes, and then extends all the surfaces at their naked edges to create a new volume. (this definition relies on Parakeet, because it’s the only place I could find an extend surface component. Everything else is native GH.)
I would like help finding a way to do this that is less of a memory hog than my solution. More on that below. Here’s the definition: Polyhedron Split and Extend.gh (78.6 KB) (thanks to @HS_Kim for a little help with part of it.)
Examples of what it does below, input brep is yellow, extension is blue:
The only way I could figure out to get decent results was to use create solid in a way that actually creates a lot of garbage output that I waste processor time on. I would like advice on how to avoid this and/or how to avoid using the Parakeet extend surface. Part of the problem is that this component untrims the surfaces, which is how I get garbage output from create solid.
In Rhino, _ExtendSrf maintains the trim of the surfaces. Could a python script achieve this? If it can, I could abandon create solid and just use brep join. @DavidRutten posted an Extend Surface component years ago, here, but the download link is now dead.
Or is there a way to achieve the same results using planes instead of surface extensions? I worry about the planes intersecting in unexpected ways, just like the untrimmed surfaces.
