Mesh Paint, using vertex color.

[Graylord]

So I am trying to use mesh paint to blend two materials. however, I cannot seem to get it right.
I connected the red channel of a vertex color to the alpha of some lerps, like explained in this tutorial:
http://www.chrisalbeluhn.com/UDK_Adv..._Painting.html

I then enter the Mesh Paint tool, and paint the mesh's red channel black (I can tell when I enter the R view mode), but I can still only see the "B" textues of the lerp.
What am I missing?

Is it possible to do it using Depth Bias instead by the way? I only want the blend to be around edges anyway. But I can't tell how to use depth bias to blend two texture samples.

[Santewi]

You most likely can't do it with Depth Biased Alpha. What version of UDK are you using? The vertex painting is working just fine for me, May 2012 build.

[mAlkAv!An]

I then enter the Mesh Paint tool, and paint the mesh's red channel black (I can tell when I enter the R view mode), but I can still only see the "B" textues of the lerp.
What am I missing?

That's actually the way it has to work. Have you tried a simple material setup first? If you plug the red vertex color into the diffuse slot directly and the mesh turns black where you painted, the problem is in the material setup.

Is it possible to do it using Depth Bias instead by the way? I only want the blend to be around edges anyway. But I can't tell how to use depth bias to blend two texture samples.

Is this for a water material or something else translucent? You can use a DepthBiasedAlpha Node for the Lerp, just make sure to increase the Bias Scale in its properties to see the impact.

[Graylord]

The painted area of the mesh does not turn black when I connect the vertex color's red channel to the diffuse. Despite it clearly being black in the red view mode.

Is there some setting I need to do in the Mesh Paint tool that I am not aware of? (I can't access the bottom of the menu, it's out of bounds)

As for depth bias, I do not wish to blend translucency, but two texture samples based on how close the mesh is to other meshes.

[JessieG]

I'm pretty sure you should be able to access the rest of the mesh paint menu if you right click your desktop, choose personalize, go to adjust screen resolution, and in the options on the right choose "smaller 100%". Sounds like you have a larger setting and it's cutting off the mesh paint menu.

[Santewi]

I'm pretty sure you should be able to access the rest of the mesh paint menu if you right click your desktop, choose personalize, go to adjust screen resolution, and in the options on the right choose "smaller 100%". Sounds like you have a larger setting and it's cutting off the mesh paint menu.

Or, just resize the mesh paint window?

[Graylord]

You can't.

My object size already is 100% (Lowest possible).

But is there anything there that's relevant? How to you paint the vertex color of a mesh using mesh paint? Is there any way to specify that?
Or should it do that by default?

[mAlkAv!An]

There is nothing below the view-channel section. http://udn.epicgames.com/Three/rsrc/...int_stroke.jpg

The painted area of the mesh does not turn black when I connect the vertex color's red channel to the diffuse. Despite it clearly being black in the red view mode.

That does sound strange indeed, if not buggy. What about different meshes and/or vertex colors?
There is usually nothing special to do. Select the mesh, select the channel(s) to paint to, set the color, paint.

[Graylord]

There is nothing below the view-channel section. http://udn.epicgames.com/Three/rsrc/...int_stroke.jpg

Ah, should have realized that when I went over the UDN page.
Thanks for clarifying.

That does sound strange indeed, if not buggy. What about different meshes and/or vertex colors?
There is usually nothing special to do. Select the mesh, select the channel(s) to paint to, set the color, paint.

When you say select the channel, you mean just untick blue and green in my case, right?
Is there a way to specify what vertex color node to use? Since materials can use multiple of the same node, and you do mention using a different vertex color. Using a different mesh did nothing.

One thing I realized is that all of the vertex color's channels results in a white diffuse rather than red, green or blue, which is interesting to me. However, that may just be the nature of vertex colors that I am not aware of.

[Graylord]

Solved it!

I just noticed this small notice on the UDN page:

Please note that the VertexColor expression does not work if the material also contains a Transform expression unless the bPerPixelCameraVector property of the material is enabled.

I am using a vector transform on one of the two speculars.