Painting obsidian

[Jackablade]

I've been assigned the lovely task of making all the rocks for our game. Currently I need to make a crystaline rock formation, specifically obsidian, and its really doing my head in. It seems like something that should be simple enough but factoring in natural looking faceting and subsurface scattering its a tricky one.

Anyone got a handy tutorial or some tips that will save me wasting another two hours fiddling with a million different techniques and filters?

[Soccerman18]

I don't know of any tutorials for painting rocks, but I would suggest starting with a reference picture such as
http://www.precious-pebbles.com/images/Gold_Sheen_Obsidian.jpg
and the modify that to fit what you want. You may also try adding a difference clouds on high contrast and erase and bit and add a bit to form the shape of the rock. Obsidian reflects light pretty well even though it's a black rock, so having high contrast will help.

[Toomas]

Do a highpoly rock and render (you propably need some plugin that can render from mesh to mesh) your texture out of it. I think it would be 10x faster than painting this kind of bugger.

[FatAssasin]

If your game supports specular maps, make sure to use one. That alone should get you half way there.

[Jackablade]

Heh, My game doesn't even support 3d acceleration.

[Illusions]

Painting obsidian...I'm trying it on my Smoke Elemental for one of the pieces, my suggestion is to only paint whatever your engine will not be able to handle. If you can, try and use a specular map, and an environmental map (for reflections). Paint it black, and include any shades from the obsidian reference that Soccerman gave you...that should at least be a start. Since I'm only doing a semi-flat surface and not an entire rock...I don't know how useful this advice is going to be...