Dynamic Paint + Transparent Canvas help needed

So I’m doing some motion tracking/compositing with real life video footage. I want to paint on a real wall. Can somebody help me figure out how to make the canvas transparent but still have the brush show up? I tried giving the canvas a transparent Alpha 0 level but no luck. As well as a shadows only button.

Hey I got this working.

You need to set the Alpha in the textures, not in the material itself (well actually it’s weird). You probably found out that setting Alpha at 0 in the canvas material makes the brush material transparent as well. Go to the Material settings for the canvas object and check “Transparency” and select “Z Transparency” but keep the Alpha 1.000. Then under “Options” make sure “Face Textures” and “Face Textures Alpha” are checked along with “Vertex Color Paint.” For some reason the canvas object needs a UV map for face textures to work. So unwrap the object (edit mode, press U, select unwrap).

Now as long as you baked the paint dynamic and scrubbed through the timeline a little to refresh it, then it should render and solve your problem. That’s why I said it’s weird, because the texture itself doesn’t seem to matter, you can turn it off and delete it and it still renders fine. Maybe it’s because the UV map is an invisible image or something. I don’t really know UV mapping yet.

Hope this helps! Let me know if it doesn’t work.

actually the way I told you is the hard way. in Dynamic Paint options if you choose “Image Sequence” instead of “Vertex” where it says “Format” then you can use that image sequence as a texture. Just make sure the object is unwrapped and ready to texture. This will give you better resolution too, so it’s probably what you want for incorporating with live footage. Then the texture should influence the color and the alpha and you’re good to go.