Alpha Matte Material?

Development Rendering
1

Rendering with Sequencer and am trying to get an image with alpha to holdout the final pixel results. I’d like a foreground object to be treated as alpha so that the object behind it is cutout by it’s silhouette.

I gave it a go with an ‘Alpha Holdout’ shading model on a material:

holdout_matte_material
holdout_matte_material1621×988 170 KB

This just casts a shadow on the object which it should be occluding. Rather, is there a way to set the material to leave transparent pixels? In this image, the cube’s top left corner would be transparent behind the sphere:

holdout_matte_scenen
holdout_matte_scenen802×634 86.3 KB

Do I need to get into Composure to accomplish this?

2

Hello, I am also searching for this answer. Did you ever find a solution?

3

I haven’t tried it yet, but I think the new features in the Render Movie Graph might address.

4

Yes “Holdout” is a new attribute on actors in 5.4 that will do exactly this.

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