A question about Channel Info (VC and Alpha)

[partycat35]

Could anyone with expertise explain, what exactly copying 0:vc and pasting it on -2:Alpha actually does.

It is a step I need to perform in order for the game to properly apply Wetness shader on the object when it rains, although there are so stuff I would like to edit for some models regarding to wetness (want to completely eliminate wetness shader being applied on some models) but since I don't have any idea what this process actually does, I am unable to generate ideas.

Perhaps if I could have a grasp on what's being done to the model with this step, I can have a better idea how to proceed with options.

[dmitriy.shpilevoy · Accepted solution]

It copies vertex color to vertex alpha. I guess shader expects a mask in vertex alpha channel to have different look on different materials(porosity) or just to exclude some areas from looking wet.

[partycat35]

Oh I see. Thank you so so so much 🙂

I will try making the vertex color black prior to copying it to vertex alpha, that might have an effect on the Wetness perhaps. Hopefully it won't take me too long to find the correct color though 😄

[dmitriy.shpilevoy]

You can visualize it via object properties. Also you don't have to copy it from vertex color, but set directly in vertex properties.

I suggest you to export a cube or teapot from max with half of it vertices black and rest white. Then check what effect it will produce in game when wet.

[partycat35]

Unfortunately the Edit Vertex Colors doesn't have an Alpha color option, only a percentage 😞

Although after you gave me the idea of Object Properties, I was able to do a better search and found a video showing an option called VertexPainting in the Modifier List. That one has the Alpha Color as well that I can see and change. Which now I can just paint the object's Alpha Color without having to go through Channel Info and copying VC to Alpha.

However very interestingly, at the beginning whenever I do that the model was losing quality (somehow) despite Vertex and Poly count stays the same. Mesh size drops from 10 to 2 MB. Then I noticed this isn't just when I use VertexPaint but happens when I use Channel Info as well.

After a lot of trials and errors, I found out if I put Unwrap UVW and just collapse it (no need to do any changes), and do the Alpha painting afterwards this issue doesn't happen. But even if I save it and then reload the save/restart Max, I still have to do another Unwrap UVW and collapse again so that issue doesn't happen. Beats me why something like this happening or how Unwrap uVW can fix it, and can fix in a way like this...

Once I was fixed it, it allowed me to realize the game determining whether should the object become wet or not, through the specular texture's color. Pink prevents getting wet, aqua makes glossy wet and green makes dull toned wet.
The Alpha Color turned out was only for which condition will make the object wet. If it is red, object becomes wet when it rains or when dropped into sea, if it's white, object becomes wet when it's not supposed to and never dries. And pink makes it half wet, gets fully wet in rain/sea and dries out to half wet condition again.