Randomizing Color with AiStandins

[aceit]

What I'm trying to accomplish is to have aistandin objects with color that is randomized between a set of pre-selected colors.

The good part is I have got this to work using the shader network below. I created a scene in which I made the shader network and exported the standins and in that scene the standins rendered just as I wanted them to.

The problem though is with most scenes that I import my standins into. When I bring the same standins into another scene they suddenly do not recognize the randomization and every instance/duplicate will render with the same color.

I know this is probably a pretty strange and unique problem but I'm at a loss here.

Any assistance is greatly appreciated!

[Stephen.Blair · Accepted solution]

It's the procedural cache. If you're importing the same standin multiple times, Arnold caches the first one and then instances it.

In Render Settings > Diagnostics > User Options, put this

enable_procedural_cache off

[joie]

Another thing you can do is use the userData attributes in order to create the random color at render time for every standin instead of having it in the original file.

See this: https://docs.arnoldrenderer.com/display/A5AFMUG/Ai+UserData+Color

I've used that workflow in a video with lots of trucks and it works perfect, and the good thing is you don't have to turn off any cache, so your rendertime is not compromised.

Cheers.

[aceit]

Thanks for the tip, I'll try that out.