Hey all,

A quick question, to which I'm sure that there is an obvious answer:

What's the best way to make a point group accumulative? That is to say, once a point has met a predetermined condition, to place it in a group (easy), but to keep it in the group even if the condition no longer applies. In the same way that POPs can keep a particle in a group if it has at any time met a condition with the “Preserve Group” option.

Thoughts?

Most likely, you'll have to use a sop solver (solver sop node) and create an attribute that does the accumulation for you, then you can use that attribute to determine the group. Sops are not history dependent, so they calculate everything on every frame. In a sop solver you get the frame before so you have something to calculate against for accumulating your values.

You don't necessarily need an attribute, Group SOP with Union With Existing Group option is your friend here. A solver is of course needed.

^Indeed, no attributes needed, I just find it easier to work that way.

Great, thank you!

It works, BUT could someone expand Solitude way?

VEX should be faster (because I've tried this group way, and is quite slow).

I've build simple “group by volume” in attribVOP, but I don't know how to store this data through time.

Tried without success AttribTransfer… but maybe solution with PointClouds may be involved?

Any ideas?