Hello,

Whenever I enter the $CEX expression to compute the centroid of my object I get this error:

“Unable to evaluate expression (Undefined variable (/obj/geo1/copy1/px)).”

I attached a screenshot of the error

you can't do that in Copy and Transform
use Copy Stamp if you want to use local variables or stamping, that stuff is probably going away eventually, as is less efficient and not compilable

The centroid expression function [sidefx.com] should work, and “0” should work to refer to the input node, e.g.

ndickson
The centroid expression function [sidefx.com] should work, and “0” should work to refer to the input node, e.g.

centroid("0",D_X)

Oh nice, I never knew you could use “0”! Thanks!

Because our expression language doesn't care about strings versus integers, you can also use

Useful tips.
Thanks guys.
But I think copy stamp is slower than H 15.5 or at least on my machine.
For example I have a ground and I want to put some packed trees on them, unfortunately Houdini immediately freezes even with low number of points!
Hope this fixes in future releases.

copy stamp will be slow depending how many instances you have, instead you should just use an @ wrangle, also make sure to pack your geo before copying.

Yes seems I have to use wrangle or VOP nods instead of copy stamping for now.
Thanks.

If it has gotten slower from 15.5, please submit the 15.5 .hip file that became slow as a bug so we can investigate.