I’m not sure if this is supported but needs some extra steps or if it would need changes in Blender itself to work.
Right now if I enable “Use Freestyle” and render with a custom RenderEngine it seems that it actually computes the results, but they are not composited into the final render.
If this requires a patch I would be willing to do the work myself as long as I recieve some direction.
July 17, 2020, 12:10pm
The way Freestyle works is that it creates a scene with meshes and shader nodes to be rendered by the render engine. Maybe the simplest way to make this work for custom engines is to always use Eevee for that instead.
@brecht. Now I get it.
I wasn’t seeing anything because the freestyle mesh has the vertex coordinates in screen-space.
I’m going to submit a patch that lets RenderEngineTypes use a flag for declaring they want to delegate the freestyle rendering to EEVEE.
It will conflict with this other patch
https://developer.blender.org/D8305. Should I handle that in some way?