Falloff mask for vertex coloring?

Z-Axis

Does anybody know... if this is even possible; how to setup a material that uses a mask for a falloff? (for vertex painting)

I've been looking at this tutorial:

https://docs.unrealengine.com/latest/INT/Engine/UI/LevelEditor/Modes/MeshPaintMode/VertexColor/MaterialSetup/3Way/index.html

The thing is, every time I paint, I get that vertex color falloff. I was wondering if I could get a crisp kind of falloff with a mask? Like paint splatters, or chipped paint?

Obscura

Yeah, you can multiply the vertex color with a mask, or you can use "power" to control the falloff.

Z-Axis

Obscura wrote: »

Yeah, you can multiply the vertex color with a mask, or you can use "power" to control the falloff.

Am I doing it right? Or do you think I could make it more efficient?

passerby

ya i use the same setup as above but i also multplt the falloff by my vcol green so i can paint falloff as well

Z-Axis

passerby wrote: »

ya i use the same setup as above but i also multplt the falloff by my vcol green so i can paint falloff as well

Sorry, I'm still learning this engine. Could you explain in a bit more detail.

passerby

ya i set it up to take a heightmap and 2 vertex colours one vertex colour does the blend the 2nd lets me paint in how hard or soft the transition should be.

I also made it a material function since i re use this a lot, and it helps to have it accessed as one node.

here is my material function.


and here is a very basic usecase for it.


i generally use the hightmap of a texture for this and blend things into the cracks, so it blends into the blacks on the heightmap first, if you need it to work in reverse you can just 1-minus your hightmap.

Z-Axis

Thanks for the info! Much appreciated.

Z-Axis

Hey, I got another question.

Right now you have it setup to paint in the cracks of the heightmap first, then the rest. How would you set it up to paint in the cracks of a normal map instead of a heightmap?

passerby

best i could think of is using dot products to find all parts of the normal map in a steep angle to create a mask, but that would be rather expensive, your best to just create a height-map.

There is no reliable way to get heights from a normal map, but off the top of my head you could do something like this, to get the edges of a normal map and use them for masking.

Z-Axis

Thanks for the info

passerby

ya i would still use a proper heightmap, or generate one from the normals offline and not in the shader.

if your worried about texture calls you could always save the hightmap into the normal maps alpha, or could save it into 1 channel of a other map.

mAlkAv!An

The blue channel of a normal already represent the slope, no need for all those nodes...



Still, the slope is pretty different from the height and might look strange if you use it as a replacement.