Okay, this has definitely been asked before as I've read a dozen threads on the subject, but apparently I am an idiot because I still do not understand how to extract data from a SOP attribute (point, detail, etc) and use it to drive something at the parameter level.

In my test scene I am creating a point attribute called “myAttrib” via a Wrangle node named “createAttrib” and assigning it a float value of 2. I'm then attempting to use that attribute to drive the Scale Y parameter of a downstream Transform node with the function:



I get an error on the transform node:

Unable to evaluate expression (Syntax error(<node name>)

I've also tried it with absolute SOP paths, and in the same test scene I'm trying it with a detail attribute / `detail()` expression, but same error.

So, how do I go about driving a SOP parameter via SOP attribute? I've seen references to using Parameter VOPs to bind outputs but after playing around with that and reading all the manual pages I feel like I am definitely missing something, or maybe misinterpreting this method entirely.

Any help would be appreciated learning the correct method of accomplishing this. Thanks!

Hi,

make sure, that the geoemtry path exactly matches the name of the input. I've modifed your file a bit, as you can see in the wrangles there are some overloaded functions of point and detail, which can be called inside VEX.

Great stuff, thanks for sharing

Found this 5 years later. Thanks for ever asking this question, you saved my ass.