Snow on rocks

NAIMA

Hello , what's you favorite technique to make snowy rocks ? I mean how you paint the snow vertically in the cracks and fenditures a rock may have and paint over the top of rocks?

ZacD

I would probably do it with a shader and maybe a bit of vertex painting to mask it. 

musashidan

You could also make use of a dust map as it would essentially affect the same areas as snow would accumulate. 

Obscura

If the client is not against it for some reason, I'd definitely go with a material based solution, because its simpler than painting, it can give better result, and because then its dynamic, and it allows you to rotate the rock and still have the snow on the top of it.

CheeseOnToast

If you bake a world space/object space normal map, you can use the green channel as a mask input. It can be used to isolate upward facing surfaces, which would naturally accumulate snow.

NAIMA

thanks for all answers, I am interested in painting directly on the rock , not using a shader etc, so a normal map green channel is the only solution ? I was thinking that may be Zbrush had some sort of tool for that ?

The same reason I could turn the question on how can I paint grass only in vertical spots of a rock or the like?

NAIMA

now that I think , my rock can be rotated in many directions , so how can I chose each time a direction ? May be in 3dsmax is there a way to apply a shader and bake that as snow?