Hi,guys.

I want to make a group of the particles,using the “popgroup”node(as in the screenshot) ,the point function is OK,but group fail,I don't know what I am doing wrong,please help me,Thanks for any help!

couple of things:
1. you can't get “Cd.x” in a point function as if needs the attribute name and attribute name is Cd which is a vector
2. you can't use just path to the node, it has to be prefixed with op:
3. be careful when using @ptnum as that refers to the current particle point number within the particle geometry which can be way different than the geometry if the color1 sop node you are reffering to

so ignoring the 3. for now as that may be your choice, it would be:

Are you just trying to group particles that spawn with that color threshold or are you try to do something a little more elaborate?

super simple would be.

Thanks to all. what Tomas Slancik said is working wonderfully.I just want to according to the color change in the sop to group paticle,it seems that the function “ingroup = @Cd.r < 0.1;” is not working in my case,I guess that the @Cd.r is not the attribute of the particle itself. Thanks all again!