Is it possible to draw texture on mesh,using a brush, just like Terrain engine?

Hey Guys,

I am looking for a solution, to let me draw texture directly on a mesh, but using a brush. it's very similar to Unity Terrain engine: you choose a texture, and select size/softness of your brush, and draw on the terrain surface. And what I need more is that the solution should output(bake) a single texture file, in whatever format is ok.

I doesn't necessary to be in Unity, if there is solution in Autodesk/ZBrush also welcome :) But at least I want if there's such solution (I believe there must be one though i don't know yet ...)

Thanks

--Michael