[jfrancis]

Say I have glossy rough plastic chipping away to reveal aluminum.

I need how many weight maps? Three?

One 80% white with black holes for the rough plastic
One 20% white with black holes for the clear glossy part

...and one black with white holes for the aluminum?

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Do I understand correctly? That's a lot of memory for 3 nearly identical maps.

[KurtS]

you need only two, because the 80% is just the 20% inverted...

[jfrancis]

Material A has two layers, an 80 and a 20

Material B has one layer.

I want to see Material B through the holes in Material A


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so I want to end up with a 3 layer material

[KurtS]

hmmm... if you post some kind of a sample image it's a bit easier to understand what you are after and how to acheive it.

[jfrancis]

See how the yellow paint rim has worn away to reveal aluminum underneath?

What if the yellow material had an 80% yellow paint layer and a 20% additive shiny highlight layer and both needed to wear away to reveal metal?

[KurtS]

I need how many weight maps? Three?

One 80% white with black holes for the rough plastic
One 20% white with black holes for the clear glossy part

...and one black with white holes for the aluminum?

Ok, I understand better now - Your first post is correct. It looks like you have three material definitions:
1) glossy surface
2) rough surface
3) aluminium

You need one weightmap for each type of surface.

I learned a lot about weightmaps by studying this example: http://www.maxwellrender.com/forum/view ... hp?t=21018

[jfrancis]

thank you