Vertex Colour & Alpha

Hi guys, I’ve been banging away at this problem and looking at tutorials everywhere but am having no luck. Basically, I want a 2 layer material, blended together with vertex paint, and then have a dirt texture blended on top, but controlled with vertex alpha.

Also, is there a way, when blending the above 2 textures with vertex paint, to have that modulated with a mask that will blend in dark areas on the mask first, then as the vertex paint value rises, it blends in the lighter parts on the control texture. That way when blending between two textures, as you slowly fade the other one in, it will pick up the deep cracks and stuff first, then fade in the surrounding surface the whiter the vertex paint gets.

Hard to explain sorry, I have this at the moment.



Black bits are the dirt, which are showing up but I can’t paint them out, which I’d like to

Cheers,
Slim