Delete POP and Point Indices

POPs
1

Salutations,

I’d like to use the delete POP to cut out a section of geometry so I can sprinkle a bunch of points onto it but I’m having an issue. The points sprinkled onto the animated geometry seem to jitter every so often. Upon closer inspection this seems to be related to how point indices are handled after my delete POP. It seems that the indices are reassigned starting from 0 (makes sense) but also seem to become eventually reassigned for some time as the animated POP moves along.

In my case, the sprinkle POP’s points works correctly while the indices move along similarly to the initial animation but jump around when they maintain their orderly range from left to right (please have a look at the example).

image
image1315×1012 93.4 KB

Delete CHOP and point indices.toe (252.7 KB)

Does anyone know why the point indices following the delete POP are behaving this way? Any ideas for how I can get them to reliably cycle instead?

Thanks,

Owen

2

Hello @owenkirby

The Limit POP in your example takes values outside the range and loops them so they are within the range. This causes the line to zig-zag and overlap itself. You can visualize this by adding a small Z-offset to the last point on the Line POP.

The Delete POP, on the other hand, keeps the points within its bounding box; sometimes, the first point of the line ends up staying at the beginning for a while before moving back. I’ve modified your file to help visualize what’s happening.

Delete CHOP and point indices.Modified.toe (261.2 KB)

3

Hi Guillaume,

Thanks for the example.I definitely see it a bit better. Do you have any recommendations for me to achieve that looping index type of behavior in a similar manner? I’m kind of stuck on this one.

4

I don’t know what your precise use case is, but would it be easier to sprinkle the mesh first, and then delete the scattered points afterward?

5

I’m working this way to try and to get as many points as possible on that small bit of geometry that’s close to the camera so I don’t waste resources creating points that won’t be visible.

It’s this sort of “infinite tunnel” type of thing which is why I have the points sliding across using a speed CHOP and limit POP. Those are then used as templates for a copy POP thus creating the tunnel. There’s maybe a better way to do this to begin with but it’s gotten me 90% of the way so far. This is just the last little bit that’s escaping me!