[Bf-cycles] SceneRenderLayers settings and 2.8

[Dalai Felinto]

Hi Brecht,

>> * mat_override [override]
>> * light_override [override]
>
> Where would the original setting be stored, Scene, SceneLayer, Object?

For material overrides the original setting would still be
object.materials[0].material.

> It would be easiest to keep these settings in the SceneRenderLayer, though
> per layer control could be useful in some cases.

Just to be clear. The idea is to get rid of SceneRenderLayer
altogether. So the settings "kept" in SceneRenderLayer will actually
be "moved" to SceneLayer.
So I don't understand what you mean by keep these settings in the
SceneRenderLayer/SceneLayer but having it exposed as per-layer as
well.

> would effectively be light groups though, which Cycles does not support.

Technically this is a special kind of overrides that is different than
the others (since it doesn't override an existing settings). Since
Cycles doesn't support it and we are deprecated Blender Internal my
suggestion is to drop this altogether actually. That said if Cycles
wants it, it can be a property of SceneLayer.

>> * lay_zmask [???]
>
> To replace this Cycles objects need to get a Holdout setting, next to Shadow
> Catcher. With overrides it should then be possible to get the same
> functionality back.

+ 1, so that would be Holdout per object + LayerCollection overrides.

>>
>> * lay_exclude [???]
>
> "lay" is for camera ray visibility, "lay_exclude" lets you make some objects
> invisible to all rays. So this would be replaced by either overrides or
> per-layer visibility settings,

lay_exclude can be replaced by not linking the LayerCollections (or
disabling them). While for "lay" we either use overrides or support it
natively in the LayerCollection.

> I don't remember if we decided on which visibility settings would be natively supported by layers.

We still need to re-visit this, it's the discussion started on D2851.

>> * pass_alpha_threshold [ViewRender?]
> Just keep it next to passes in SceneRenderLayer I think, not sure why you
> would need this in ViewRender, it's about how render passes handle alpha.

+1. I actually got Sergey suggesting exactly that, but I forgot to
update this before sending this email.

Thanks,
Dalai