Surface disappearing

When I am splitting a surface it disappears. It seems to create a fine solid, but when I bring it into a slicer program it does not look ok. I tried the Refreshshade command, and I also rebuilt the model from scratch. I would love to know why this is happening. Thanksbay finished.3dm (3.5 MB)

Hello - Rhino is unable to create a usable render mesh from at least one of the faces in the object… I’ll see if I can figure out which one - often this is traceable back to a looped trim curve, which seems likely here.
@cwreckord - I don’t see it yet, but I do notice that your bar on the bottom has self intersections - a separate problem but you’ll want to clean that up:


Thanks @pascal! I tested for self intersections on the curve and extrusion- but I modified the shape of that bar and didn’t realize that it did that. thanks!

Hm - ok, I found it - there is a self-intersection here:



ohhhh thanks. You don’t know how long I have been working on this model. I am so so appreciative if your help. Do you have any idea why the testcrvselfintersection did not catch this?
And is there another command I could use instead?
Thanks again @pascal

I noticed that too - I’ll send the example on to the developer.