Boolean Difference Failing

Hi, i’m trying to make a boolean difference with two closed polysurfaces and i don’t know why it fails. From what i can see, both polysurfaces are intersecting and they are both closed.
Can someone help find the error?

Help.3dm (6.7 MB)

Hello - yeah… I do not see it yet either - the red thing seems a bit more complicated than it needs to be but I’d expect this to work from what I see so far.


The issue is with some thin surfaces at the top of the pattern cutter. Here’s how to fix it…

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Thank you @BrianJ !!! How did you realize it was that? it seems like a hard thing to detect. is there a tool to look for those kinds of things?

The first thing I do when a Boolean fails is to run Intersect on the objects and inspect the crvs created. SelClosedCrv or SelOpenCrv for instance would show problem areas. That didn’t identify the problem so I then started looking for surfaces in the intersection areas that looked too complicated and found that spot. Extracting and deleting bits led to the discovery… I bet that an offsetsrf caused it due to a split edge from some other operation. That thin srf was probably getting joined in so everything still said closed but caused some overlap in the intersection resulting in the failure. It’s a hard one to find admittedly, glad that helped :slight_smile:

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Thanks for the tip!