Transparent Backgrounds with Filament

foxwhowood_92d4a5ae49

I'm a mid-level Studio user. Recently I've been experimenting with Filament rendering to speed up producing animations. In Iray turning "draw dome" and "draw ground" off leaves the background transparent so I can layer the animation in Premiere. However I can't get my Filament renders to do the same thing. The backgrounds always come out opaque black. What do I need to do?

jbowler

Filament can do it: https://github.com/google/filament/issues/1441, but it looks like Studio is creating an RGB buffer; at least both the PNG output and a canvas (EXR, TIFF).  There's nothing in the Filament Draw Options node (which has to be created manually) to fix that.

You could try green-screening, indeed you could even use the GIMP to fill the black background with an alpha channel, but black screening doesn't work well because it's impossible to stop it bleeding into the foreground (the screen color has to have at least one color component 0 and another 1.0).

cain-x

What format are you rendering to? It should be an Image Sequence set to either png or tif. You will see the alpha in those formats. Also, check the Environment tab and make sure it is set to None.

jbowler

Hum.  Forget what I said; I don't know how to do a Filament render.  I did once but clearly not now.

Select "viewport" in the render engine settings (dropdown), render.  It's instant and it has alpha (I did it from scratch; it has alpha by default).