Surface Volume Test Explanation

[leejk]

Hi,

So in the attached I am simply trying to test if the particles are within a certain volume and if true, assign them a different material id and display color. However as simple as that sounds it does not work, so obviously I am not understanding something obvious, as I have seen other examples that work. Does it have something to do with the fact that I am using particles from another flow?

thx

[leejk]

So this is more complicated than I thought. I'm wanting to do 2 things here:

1) Tag only particles that are within the volume of the bucket
2) Assign them a tag that can be used in post to mask them, like Object ID

The first part though is proving difficult. As the volume moves through the mass of particles it should test whether or not a particle is inside or outside the volume. Here is my attempt at this, but it does not seem to work. As far as I can tell, VRay is picking up the Instance ID operator assignment in it's Render ID render element, but there's no documentation anywhere to verify this is right.

Anyone have any suggestions?

[d4rk3lf]

I am using surface test (volume inside and outside), all the time, and never had any issues.
2 things that crossed my mind:
1) Is your volume object closed mesh? If not. Try making it closed... add a cap holes modifier, or model primitive (closed) version of the model to use for a surface test.
2) Double check that surface test operator timing is set to continuous (should be by default.. but no harm in checking)

[leejk]

I am using surface test (volume inside and outside), all the time, and never had any issues.
2 things that crossed my mind:
1) Is your volume object closed mesh? If not. Try making it closed... add a cap holes modifier, or model primitive (closed) version of the model to use for a surface test.
2) Double check that surface test operator timing is set to continuous (should be by default.. but no harm in checking)

Hello,

Yes, that was it, it was not a closed mesh. The other issue was that I was making my graph more complicated than it needed to be... finally got it working late today and rendering it out now.

thx