Split surface using curves

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Permalink Reply by Damien Alomar on October 3, 2009 at 10:07am

Well, I actually asked Steve Baer about this while I was up in Seattle back in August. There really isn't any way of doing this with the SDK, and the recommended method is to extrude the curve to get the brep and use that to split the original brep.

The other method which I've used (but was kind of a pain) was RhUtil.RhinoCutUpSurface as it will work with curves. There are a few stipulations with using this. First, it will only take an OnSurface, so essentially you'd need to be working off of a single face, untrimmed Brep in the first place. Secondly, sorting through the output is a little annoying as the output tends to be a single brep split into different faces (ie you've got to cycle through each OnBrepFace)

You may want to take a closer look at how you're generating the curves. Most curves that you would trim with can actually can be generated from interesecting surfaces/breps. For instance Projecting can just be made by extruding along the projection vector and a section can be made by making a big surface from the plane. Doing something like that might be better than just using the curves.

Permalink Reply by Nathan Hoofnagle on November 1, 2009 at 4:09pm

I've been trying to split an untrimmed open brep surface forever and nothing seems be working. What exactly is the RhUtil.RhinoCutUpSurface? A component or a script using VB? Maybe this could work.

Permalink Reply by Damien Alomar on November 1, 2009 at 8:08pm

Its a method exposed by the SDK, so you would need to utilize it within a scripting component.

Permalink Reply by Vicente Soler on October 3, 2009 at 11:23am

Check out this thread:
http://www.grasshopper3d.com/forum/topics/surfacetrim-workflow

Using the RhinoSplitBrepFace method, the splited object has to be a brep not the splitter.

Permalink Reply by Thomas Bildsøe on October 4, 2009 at 3:16am

Thanks both of you!

I'm using the extrude method right now, and are going to test the SplitBrepFace method to see which one works best.

My biggest problem with the extrude method, is that im dealing with curves and its not allways possible to find a suitable extrude direction.

The CutUpSurface seems to excessive to control.

But thanks guys.

/Thomas