How to isolate the intersection/highest values of already combined vol

[magneto]

Hi,

 

If you already have a geometry that has multiple pieces and it's already converted to points, how can I isolate the certain parts with max values?

 

It looks like this:

 

 

So I want to get the parts where the geometries would be intersected (they are spheres).

 

Is this possible? I know with volume merge but that requires the volumes/geometries to be separate.

 

 

Thanks

[anim]

depends on how you combined them

if you combined using max/maximum method, there is no way how you can separate it afterwards with no other hint, as it is now single density volume where intersected parts were copied from voxels with maximum value

if you combined using  add method and the volume spheres had (in best case scenario) constant density of 1, then you can use f@density = f@density > 1 ; to get intersected parts

[magneto]

Thanks anim. I had the spheres as spheres copied onto points and then simulated (RBD), then the result of that DOP import is converted into a fog volume. So I guess in this case the parts where these geometries intersect won't have increasing values, right?

 

Do you use the code you just posted, in a new volume by sampling the second input so that I can create a new volume where I only have density in those intersections? Basically can I purge the rest of the volumes outside the intersected regions?

 

I am trying to do this but using the packed prims, there is no volumes built for the objects:

 

 

Is there a better way to do this than shown in the video?

 

 

Thanks again.

[anim]

for intersection with the ground you can keep them together, however you probably want intersections among each other

 

in case there is constant amount of pieces during the sim, the fastest way would be to:

1. generate VDB fog volumes from initial pose of your packed RBDs within foreach ( = evaluates just once)

2. move resulting VDB volumes according to imported RBD points from sim

3. since they are individual VDBs you can do the VDB combine with Add mode

4. append Volume Wrangle with mentioned: f@density = f@density > 1;

 

the slower way of course would be doing foreach for unpacking/generating VDB fog volumes on every frame on geometry coming from sim

I can post file later if you need one, can't from work

Edited June 6, 2015 by anim

[anim]

or you can as well convert them to SDF first, the Dilate a bit (VDB reshape SDF) and then convert to fog so you have some detection offset fot intersections

[magneto]

Thanks a lot anim, I will try to do it myself and report back