Hi, I'm new to houdini. I don't understand how “AttribFromVolumn” work. Which attribute of the volumn does it take?

It uses the points from the first input as positions to sample into the volume primitives in the second input. It then puts the result into an attribute on the points (of the first input). The tuple/components size of the attribute should match the volumes that you set in the Volume parameter. Since Houdini Volume primitives are always scalar fields, then you should specify 1 volume for each component of your attribute.

edward
It uses the points from the first input as positions to sample into the volume primitives in the second input. It then puts the result into an attribute on the points (of the first input). The tuple/components size of the attribute should match the volumes that you set in the Volume parameter. Since Houdini Volume primitives are always scalar fields, then you should specify 1 volume for each component of your attribute.

Thank you for your reply!! But I still wonder, coz there's no parameter that specifys which attribute of the volume does it take. For example, what if there're more than on attribute that are stored on the volume, eg. density, temperature, pressure…

A volume primitive does not have multiple attributes per voxel. So density is a separate volume primitive from temperature, for example.

edward
A volume primitive does not have multiple attributes per voxel. So density is a separate volume primitive from temperature, for example.

Got it! Thanks so much