debugging complex boolean ops

[stewartoallen]

I've integrated Manifold into one of my more experimental projects, a mesh editor, which I often use as a playground for testing new capabilities that I want to add to my slicer. Using stock Manifold without my recent PR changes, I'm having difficulty debugging complex boolean on some objects. It's not clear to me how to proceed.

To start off, this is a simple test of union and subtraction.

This is a more complex test I have been doing with the jscad/modeling library involving 3DBenchy. Manifold just seems to ignore the benchy. But when I ask the API, it says all objects are manifold.

I know it's not a memory or complexity issue, because Benchy only has 225K faces, and this next Twisted Flutes model has over 2M, and it completes both tests.

Any pointers appreciated!

[stewartoallen]

I should add that the mesh editor also has a repair feature that looks for, reports, and patches defects like open edges, dangling and invalid faces, etc. That code does not find any anomalies.

[stewartoallen]

I don't mind just getting the first thing to trip up the parser. It's at least a starting point for fixing something. I can also learn from that to improve my model sanity checking code.

[elalish]

Oh right, we gave you an empty mesh, which is manifold by default. Yeah, IsManifold isn't really meant to be a public method; it was for testing, but is probably not needed anymore. We should just remove it to avoid the confusion.

[elalish]

I would guess that debug will be easier if you write your own manifold checking function: there's not much to it. But if you come up with something that seems generically useful, go ahead a make a PR for it.

[stewartoallen]

it looks like normals inversion on some faces. this is something that's easy to highlight or fix by letting the user click one known good face and the engine can sort out the rest from there.

[elalish]

SG, as long as it's not a Klein bottle.