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Maniphest T70428

CYCLES: Surfaces inside volumes are Not Lit or Shadowed by the volume if the volume is not visible to Camera Rays
Confirmed, LowPublicKNOWN ISSUE
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Description

Linux Mint Mate
GTX 1050

Blender 2.81 Alpha
2019-09-27 22:44
Hash: 1c1a3198af9d

Discovered while trying to catch shadows from volumes on surfaces for compositing.

Surfaces inside of volume meshes are not shaded (lit/shadowed) by the volume if the volume is invisible to camera rays
(checkbox in Object Properties -> Visibility -> Ray Visibility -> Camera)
As far as i can tell this also affects Holdout.

Current workaround: make sure volume IS visible to camera rays, and instead bypass it in the volume shader using the Camera Ray socket on the Light Path node

To Reproduce:

Open attached .blend , press render
Note the missing shadow/light where the volume cubes intersect the default cube.

I have in the .blend also included the "expected behaviour" by using the workaround, switch the Scene from "Bug" to "Workaround" and press render again.
Note the shadow/light now covers the default cube properly.

Related Objects

Event Timeline

Matthew Wiebe (cerebral_malfunction) created this task.Oct 1 2019, 10:25 PM
Brecht Van Lommel (brecht) lowered the priority of this task from 90 to 30.Oct 2 2019, 6:48 PM
Brecht Van Lommel (brecht) added a subscriber: Brecht Van Lommel (brecht).

It seems the .blend file didn't get attached?

Brecht Van Lommel (brecht) added a project: Cycles.Oct 2 2019, 6:48 PM
Matthew Wiebe (cerebral_malfunction) added a comment.Oct 2 2019, 9:29 PM

strange, the download link worked in the report preview. I have tried again.

Cycles Volume Camera Visibility Bug.2.blend675 KBDownload

Brecht Van Lommel (brecht) raised the priority of this task from 30 to 90.Oct 2 2019, 11:15 PM
Germano Cavalcante (mano-wii) assigned this task to Brecht Van Lommel (brecht).Oct 3 2019, 2:03 PM
Germano Cavalcante (mano-wii) lowered the priority of this task from 90 to Low.
Germano Cavalcante (mano-wii) added a subscriber: Germano Cavalcante (mano-wii).

I can confirm.
You can easily observe by selecting one of the invisible objects and enabling the Ray Visibility Camera option.

Dalai Felinto (dfelinto) removed Brecht Van Lommel (brecht) as the assignee of this task.Dec 23 2019, 1:48 PM
Dalai Felinto (dfelinto) added a project: Tracker Curfew.
Brecht Van Lommel (brecht) changed the subtype of this task from "Report" to "Known Issue".Jan 27 2020, 11:34 AM
Brecht Van Lommel (brecht) edited projects, added Render & Cycles; removed Tracker Curfew.
Matthew Wiebe (cerebral_malfunction) added a comment.Dec 25 2020, 12:01 AM

Is this fixed by https://developer.blender.org/D7860 ?

Pratik Borhade (PratikPB2123) mentioned this in T99307: Turning of camera visiblity for volumetrics bugs shadows.Jul 1 2022, 6:46 AM
Pratik Borhade (PratikPB2123) merged a task: T99307: Turning of camera visiblity for volumetrics bugs shadows.
Pratik Borhade (PratikPB2123) added subscribers: Gurra (Gurra), Pratik Borhade (PratikPB2123).