Paint FX problem
 

I'm using tomcat cartoon shader to get a hand-drawn look for some models. I'm using the "noise" function under tubes and repeating a cycle of ten keyframes to get the lines to jiggle around realistically. The problem is, although "screenspace width" in the PFX attributes makes the width of the brush the same no matter how far the stroke is from the camera, but does not make the noise etc. behave as if all the strokes were the same difference from the camera. As in, the stroke width is not affected by perspective but everything else is. So my noise works nicely for objects close to the camera, but for objects further away it seems completely nonexistant. Does anyone know how to make it so that the noise is constant no matter how far away it is?

Here is a simplified and somewhat exaggerated sample:

http://img15.photobucket.com/albums/...ice/sample.jpg

I've got some problem like this with a graphic board not efficient. Lack of VRAM.