Vertex paint is a modifier that is mostly used in the game development industry but for some reason is almost never used in architectural visualization. However, there are quite a few situations where it can be very helpful due to the fact that you can blend materials anyway you want by painting maps directly on the mesh.
In this example we will try to “paint” a pathway on a hilly landscape.
Start with a 30mx30m plane object and add around 100 length segments and around 100 width segments. Covert it to editable poly and drag vertices on the z axis, with soft selection active, until you get something similar to the following:
Assign a blend material to the geometry. In the first material slot (inside the blend material) apply a grass texture, and in the second slot apply a gravel/sand map (this will be the texture for the pathway). Don’t forget to add a planar uvw map to the mesh adjust the tiling until you are happy with the result.
In the “mask” slot, choose “vertex color”, like in the screen capture bellow.
Now add a vertex paint modifier to the geometry and using the brush tool, paint a black pathway wherever you want. You can easily adjust the size of the brush to anything you want.
Believe it or not, that’s all. If you hit render you should end up with something similar to the following image.
As I said at the beginning of the tutorial, there are several situations where you can use the vertex paint modifier: you can use it to add more variety to large surfaces covered with grass, concrete walls, or even create tire tracks.
*If you use vray, than use the “vray blend material” instead of the “standard” blend.
