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taiya / dgp

Digital Geometry Processing - Fall 2016 - University of Victoria
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How to detect an "invalid collapse"? #11

Closed xuzheng0927 closed 7 years ago

xuzheng0927 commented 7 years ago

This is from the assignment description: "Invalid collapses are defined as the ones that produce a non-manifold configuration (or a face fold-over)." For the face fold-over, we can use the threshold provided by the base code (min_cost). What about the "non-manifold configuration"? Any rules (or do we need to deduct the rules ourselves)?

taiya commented 7 years ago

Check the SurfaceMesh API ;)

nlguillemot commented 7 years ago

There's also some discussion about this in the polygon mesh processing textbook.

xuzheng0927 commented 7 years ago

I found an "is_manifold" function. So how do we "simulate" the collapse? I plan is to associate all vertex v0's half edges with the v1 (the one to be collapsed into) and remove v0, then check whether it is valid. If not I'll create v0 and associate those half edges back. But it seems it is not "simulation".

taiya commented 7 years ago

That's not the right one. Peek around "collapse" (I already said too much ;)

As for the simulate, you'll have to think about it yourself. There is nothing wrong in discussing with colleagues (as fas as you don't look at each other's code)

xuzheng0927 commented 7 years ago

Solved and will closed the issue.