Curve.CreateBooleanUnion and Regions

Hi,

I am a bit confused about the inner workings of Curve.CreateBooleanUnion and how Regions are managed in Rhino (if they are), because there seems to be no specific type for Regions.

If I have a list of closed curves that are co-planar and I use Curve.CreateBooleanUnion, the Rhinocommon SDK says that it will return an array of Curves. This seems fine; from my understanding the array must include the outline curve and the inner holes, but what if Curve.CreateBooleanUnion creates a number of different regions, i.e. seperate outlines with inner holes? How are these formatted in the returned array of Curves such that I might be able create a list of Planar Surfaces from them or Hatches?

Any help or advice is much appreciated.

Thanks,

Adam

Replies to This Discussion

Permalink Reply by Andrew Heumann on August 11, 2012 at 9:59am

If I'm not mistaken, Brep[] CreatePlanarBreps(IEnumerable<Curve>) will handle this situation just fine - it will automatically detect which regions are outer boundaries and which ones are holes. Similarly with Hatch.Create.

Does that answer your question? were you running into trouble doing this?

Permalink Reply by Adam Holloway on August 11, 2012 at 2:38pm

Hey Andrew,

Thanks for your reply. That method works great! I had been searching in vain for it in relation to creating surfaces because of how it is categorized in rhino and grasshopper, and I didn't think to look for a brep method...

Permalink Reply by Adam Holloway on August 11, 2012 at 6:02pm

Planar Breps seem to be a bit heavy to use for organizing the curves. I am trying to do it by creating hatches now, but there doesn't seem to be a way of accessing the boundary curves of the hatch after you create it? Do you know of a way? Or is this only possible with Surfaces and Breps?

Permalink Reply by Andrew Heumann on August 11, 2012 at 6:35pm

hatches are EXTREMELY poorly implemented in rhinocommon. As far as I know there is no way at all to access the boundary of a hatch; I've been trying myself for some time. http://www.grasshopper3d.com/forum/topics/hatch-explode

Permalink Reply by Adam Holloway on August 11, 2012 at 7:13pm

That's unfortunate...

Is it possible to get access any of the geometry of the hatch object? Or does hatch.explode always give you an empty array regardless of which hatch type it is using?

Permalink Reply by Andrew Heumann on August 11, 2012 at 9:23pm

hatch.Explode will give you the curves that constitute the hatch, or a trimmed planar surface brep if the hatch is solid.

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