How Does the "Copy From Vertex Color" Option Work?

In the Active Cloth Paint mode in the character mesh window, there is an option called Copy From Vertex Color used for creating masks for cloth simulation. How do I use it? Is it referring to the Material Editor? Do I use it by attaching a grayscale map to a color channel in the Materials Editor? How exactly do I set it up?

https://docs.unrealengine.com/Images/Engine/Physics/Cloth/Overview/CopyFromVertexColor.jpg

The UE4 Documentation on this does not explain this very well.

It references vertex colors, which come from vertex maps. You can paint vertex maps in 3D apps (such as Maya or C4D) - or you can paint them inside of UE using the Paint mode. When importing FBX files that contain vertex color maps do this:

FBX import options > Mesh > Advanced. Set Vertex Color Import Options to Replace.

Thanks for this, However Im trying to find the same thing with the Alembic file, I created a simulation in c4d and make some texture maps for velocity, age, speed… When I created a blend material in Unreal using Lerp, and vertex color as alpha… It did automatically loaded 1 Texture Map, however I need to use the other 2. How can I access them ? Please help.

In .25.2 the option doesn’t work.
Vertex paint is present on the mesh and can be visualized, for instance in my case it fades from red to black.
importing the red channel should therefor show some gradient results. Instead the mesh is just painted to 0 values - b black, not pink.

Ok, an amend to that.
The copy function DOES work, but it keeps on using whatever data was already in place BEFORE you created the cloth data.
So the vertex data isn’t changed by simply re-importing the cloth.
That means that for every change you have to delete the cloth data, import, and re-create… painful.

Hello @MostHost_LA,
Can you be more specific as to how you managed to use the Copy From Vertex options please?
I am unable to use it and I always get 0 values like you mentioned. Thanks a lot
Have a nice day
Theo

Try this

Hey, MostHost_LA,
Thanks for the tool it is great and I am sure I will be using it going forward.
Yet it seems the trouble is with UE not copying the vertex data in the mask. I get 0 values all the time even when using your tool that helps isolate vertex chanels. Also it is kind of frustrating since I make sure that UE is getting the vertex colors from import by displaying it.
I thought is was due to me using UE5, but I have tried UE4.27 this morning and I am no more able to use vertex color for cloth painting.
Surely I might be doing something wrong but I am yet to figure out what it is.
Thanks a lot for your helps
Have a nice day
Theo

It’s much more likely that Epic broke NvCloth.
They don’t care / won’t care since it’s supposed to be replaced with Chaos Cloth some day.

I haven’t actually tried to paint cloth in a long, long while.

As a general rule of thumb start by putting your mesh in world, and adding a material that uses RGB of vertex color as the base color to confirm that the mesh actually HAS vertex colors.

From then on, if the option to use vertex color doesn’t work, then they broke the engine…

PS. the tunic file is still available from the video description. I Think I published that with vertex paint on it, so you could potentially import and try panting that…

Hey @MostHost_LA,
Sorry I am logged in with a different account today
Update to my last post, it seems it is all working fine today up to UE5.
Some way I might have managed to pull a string of bad trials on my side
All good now
Thanks for your help
Best

1 Like