How I can target primitives with a certain attribute value for a collection? Or in other words, how to use attributes a Vexpression for something in lops?

I want to create a collection for that includes primitives given the value of an attribute they have.

Any help is appreciated !

Thanks

It's the same format as the VEXpressions you can put in any Primitive Pattern field in LOPs, described here: https://www.sidefx.com/docs/houdini/solaris/pattern.html [www.sidefx.com]

All the USD related VEX functions start with “usd_”, so they're easy to find in the VEX documentation.

How would one make a VEXpression that compares a primvar value?

I attempted to do and it hanged so bad I did't even get a core file when I killed it.

try

npetit
try

vector(usd_primvarelement(0, s@primpath, "displayColor", 0)).r > 0.5

okay. That sounds equivalent though.

jsmack
That sounds equivalent though.

I haven't looked into it but I think your would requires that primvar is, or assume all primvars are, bound to a VEX variable. Using the query function as per Nick's example doesn't have that requirement.

jason_iversen

jsmack
That sounds equivalent though.

I haven't looked into it but I think your would requires that primvar is, or assume all primvars are, bound to a VEX variable. Using the query function as per Nick's example doesn't have that requirement.

Right, I guess I assumed they would be, but maybe not. Maybe they are only bound in the context of wrangles?

jsmack
I attempted to do

v[]@primvars:displayColor[0].r > 0.5;

and it hanged so bad I did't even get a core file when I killed it.

This should be fixed in tomorrow's H18.0.446.

Awesome!
Thanks