Hello everyone.

I have an scene with some spheres (each one in a different group), and I add it to DOPs with a rbdfractured. I want to group the spheres with the Group DOP by a prim attribute created in SOPs. I use
, but there isn't any result…

I attach the scene file.

$OBJ is the unique object number of your sim, which makes it tricky to use in your prim() expression.

Try changing $OBJ to ($OBJ-1)*20
The *20 is because there are 20 primitives per sphere.

Thank you very much Wolfwood. It works perfectly.

The spheres scene was only to show this question, but in my real scene (each group has a different number of primitives) it works correctly.