Maya particle expression not updating correctly

I'm doing some terrain modeling and I'm using textures to displace a soft body mesh. This is fine when I use 2D textures and "colorAtPoint". But when I wanted to use some solid textures, the problems start.

I use a run-time expression to input my particle's world position into the refPointCamera attribute on the solid texture. I read the solid texture's output and use that value for displacement. I'm also using it to assign rgbPP values so that I can see what I'm getting is correct. The rgbPP values are correct but the displacement values are not. After the expressions have evaluated, I run "currentTime (current frame)" and then my displacement matches my rgbPP.

I also noticed that my rgbPP updates differently depending on whether I update the frame interactively, or during playback/playblast. Very strange.

Any ideas why this happens?

Add comment viewed 476 times Latest activity 7 months ago

mike rhone Dec 2, 2010

Have you tried 'forcing' it to evaluate by doing a getAttr/setAttr mel in the expression? Messy and slow, but might work in a pinch.

NN comments

Interesting idea. I’ll try it out when I get a chance to revisit this. Thanks.

Dec 4, 2010

Julian Mann [ Admin ] Jul 14, 2010

Have you tried animating a bunch of attributes? Sometimes that can help force things even if the curves are static and the values don't actually change? The fact that time is in the dependency chain may help..

NN comments

I’ve tried an animation. That’s how I noticed the difference between interactive frame by frame updating versus playback/playblast.

Jul 14, 2010

bernie Jan 13, 2011

I don't think you can use a solid texture with colorAtPoint. Bake your procedural texture to maps.

NN comments

What's your question?

Maya particle expression not updating correctly