Get proper shadow from Layer Shadows

[BadBilly]

Scene test file - https://we.tl/t-SWToIr4HXs

So this is something that has plagued me for a while.
When I do render layer - layer shadows on a more complex scene (ie, more than an object and a plane) - I find I get a lot of extra shadows from different objects, including self-shadowing (that arent supposed to be visible) and even sometimes shadows when there shouldn't be. For example, in the attached render scene, there is a box covering the red cube, blocking it from light. Yet, the cube still casts a shadow.

Is there a work-around to solve this issue?

Thanks.

[bepeg4d]

Hi,

What happens is you place the big cube (with its own material) as a child of the red cube?

ciao,
Beppe

[BadBilly]

It just creates darker shadows on the contents inside.

[bepeg4d]

So the light is blocked, and the red cube doesn't produce extra shadows.

ciao,
Beppe

[BadBilly]

But there is still an issue? The shadows of the other objects still exist (and not accurate shadows at that). It should only be the shadow of the render layer, not the entire scene.
It’s like apart from simple planes, render layer shadows does not work/ is buggy, and shadow catcher isn’t any better. This is something I constantly battle with as I regularly composite renders into live action footage.

[bepeg4d]

Yes, definitely not easy to use it in complex lighting conditions, mostly because if an object is not affected by Render Layer ID, it is invisible, so it cannot interact with light, apart from receiving shadows. You need masking objects with same render Layer ID, and maybe hiding them with Octane Object tag Visibility.

ciao,
Beppe