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Ellyfish

Voronoi fracture ignores some fracture points

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This keeps coming up so I'm afraid I'm missing something, but I'm not sure what. For voronoi fracture, I plug the object I want to fracture into the first input, and the points around which I'd like it to build voronoi cells in the second input. Sometimes, this does exactly what I want. Sometimes, it ignores some of the input points. For example, in my image below, I've plugged in 8 points, all of which are inside the geo, but it's only generated 5 pieces. Has anyone encountered this before, and if so, what did you do about it?

temp.jpg

EDIT: If I throw a pointvop between my input points and the voronoi SOP, randomly offsetting all points by a tiny random vector, it works. Does it not like when points are in a row?

Edited by Ellyfish

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You're inside a loop there... what exactly is that doing? I have a feeling that's probably the source of your problem. Can you post the .HIP?

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The .hip is huge and would probably just confuse things. The loop is just going through a bunch of different blocks and breaking them all separately. All the others that it loops over seem to break up how I'd expect, just this one is being weird.

I offset the points by a tiny random vector and it worked. I'm not sure why. Does it not like collinear points?

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this simple test proves it works fine...dial up the number of points in the line...

(are you doing any clustering ?)

LinearVoronoi.hipnc

 

Edited by Noobini

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Hmm. Sometimes, like this time, I'll scatter some points and fracture, then make new points at the centroid of each fracture piece and fracture the original geo with those points a second time. That helps even out the spacing and fracture into straighter lines; for example if I have a long thin block that bends, and I want it to be fractured into pieces lengthwise, but don't know its orientation or exactly when the bends happen. I know I've run into this error before; if there's not some obvious case that causes this kind of problem then I'll assume it's got something to do with that and just keep on adding a small random offset.

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ahhh got it, so my little test works fine.....or so it seems, just chuck in a sort after the line, and randomize the point order you'll see it's scrambled.

So I guess if you know you've got your points pretty much 'linear' you might as well sort them in a certain direction, that should fix it.

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