MeshRenderer CastShadows [OFF] disables baked GI shadows

Hi,

I have updated project to Unity 2019.4.28 and the Cast Shadows parameter on Mesh Renderer component behaves differently now.

* When I set Cast Shadows to OFF, none of these objects cast lightmapped indirect shadows after baking.

This is either a bug or completely different behavior from previous Unity versions I used (most recently 2019.1).
Originally the parameter influenced only direct shadows, not baked indirect. This way I can't have fully baked shadows and hand-pick which objects cast dynamic shadows and which do not.

The only way would be to create a script, which would disable dynamic shadow casting in Awake or Start, but that is just stupid. If somebody decided that setting Cast Shadows to OFF should also disable indirect, baked lighting, then you should have added a separate parameter for that.

 

Hi,
I mainly use GPU lightmapper.

I've tested it now with the CPU lightmapper and lighting is correct! So it must be related to GPU lightmapper.

Object on the LEFT has Cast Shadows ON and on the RIGHT has shadows OFF.
As you can see the image on the right is not correct at all. It looks like a diffuse with GI additively slapped onto it.



They have indirect lighting from environment (ambient) color and one single directional light. The material used is default diffuse to rule out the shader. Could you please test it with GPU lightmapper? Could GPU drivers have any impact on this?

 

Well that is really weird. I've created completely fresh project with one mesh and a single scene. The result is the same:
.

Project files are here as an attachment and bugreport has been sent.

(Case 1348581) Indirect Environment Lighting broken with Shadows OFF and GPU Lightmapper

 

Can confirm on 2020.3.13f1


It has nothing to do with the Direct Light. I actually deleted the Directional Light in this test.

It seems like Cast Shadows also affects indirect light (maybe only from environment?), although it used to be only for direct shadows.

Not sure if it's a bug or a feature.

It could be a feature, I can actually think of a couple of areas where it would be useful to me, BUT, ideally these would be decoupled and I could turn cast shadows on / off for direct and indirect separately.

It is also consistent with the CPU Lightmapper. For me GPU and CPU produce the same results.

The corners look like they are brighter, because light does bounce around it, but it doesn't get occluded. So it has the inverse AO look.

If I limit the bounces to 1 it looks like this :



Since the mesh doesn't occlude the light coming from the environment, it becomes almost uniformly lit.

 

@kristijonas_unity
Is there any update? Have you been able to reproduce the issue?

 

@Jesper-Mortensen
Is there a time-frame for backport to 2019.4.x? I'd like to know because it might change our release plans a bit. All I can find is "Planned for 2019.4.X".