Object won't split? Can not figure out why.. can someone help?

I have tried several options like rebuilding sections, separating sections, nothing works. There are no naked edges, no non manifold edges and all poly surfaces are normal. I want to split this in half right down the middle to make 2 sides (left and right). Can anyone tell me why this won’t split and how to accomplish my task? Thanks in advance!

Edit: can I attach a file here?

If you are having trouble attaching a file, please send it to tech@mcneel.com. You should be able to attach files here but there may be some rules about posting so many times before allowing an attachment or something like that, I am not sure where we stand on that at the moment.


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Thank You, just sent an email.

There is a “test” command in V5 called “TestOffsetPolysurface”. It is a test command because it is not ready for “prime time”. It took several of minutes of number crunching time to offset it by 0.1mm (Your object is quite small), and created a “bad” object that needs to be cleaned up, but it was a lot faster than manually offsetting each surface individually and trim/extend/join to do the work manually. It left a lot of naked edges too so there is lots of clean up work to do.

There is no automatic way to do this yet. It’s still a bit of a job.

  • John Brock [Technical Support]

Hmmm- OffsetSrf is the command for ‘thickening’; no test command needed. However the object you posted does not offset very cleanly, I’d have to look more closely at what that may be. The other object you sent, the one to split— there is no indication of an object that you want to use as the splitter.


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Sorry… I have no idea what this means…


I have no idea what that text is either. Did you get the reply email that included the file of the object that I want to split with a splitting object?

It looks like replying by email and including a file attachment fails. This is a bug that @sam can comment on.

I did get it, thanks. I am not sure if this is the sole cause of the failure but the area marked in the image has a lot of surfaces coming together at one location- probably ought to be flagged as non-manifold in ShowEdges but it is not… need to look at that a bit more. At any rate, you might want to resolve that area a bit better, thinking of it as a solid without zero-thickness allowed, that might be easier. Meantime, I workaround might be ExtractSrf with a window selection in Top or Front and carefully windowing one half, just touching the centerline’s ‘far’ side.

There are a number of locations where this model could be simplified with trimmed planes by the way.