Maniphest T70064

Mute RGB to BW converter node doesn't work in Cycles rendered
Closed, Duplicate
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Assigned To
None
Authored By
Emmanuel LORANT (asturias)
Sep 19 2019, 11:51 AM
Tags
  • Cycles
  • BF Blender
Subscribers
Brecht Van Lommel (brecht)
Clément Foucault (fclem)
Emmanuel LORANT (asturias)
Jacques Lucke (JacquesLucke)
Philipp Oeser (lichtwerk)
tom k (tomjk)

Description

System Information
Operating system: Windows 10 x64
Graphics card: 1060 + 1080 Ti

Blender Version
Broken: Last one : blender-2.81-741d7d60ed90-windows64
(example: 2.79b release)
(example: 2.80, edbf15d3c044, blender2.8, 2018-11-28, as found on the splash screen)
Worked: (optional)

Short description of error
As title says
Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
Create a new material with a RGB to BW node. Mute it. It works in Look Dev mode, not in Rendered mode with Cycles (it works with EEVEE).

Event Timeline

Emmanuel LORANT (asturias) created this task.Sep 19 2019, 11:51 AM
Jacques Lucke (JacquesLucke) lowered the priority of this task from 90 to 50.Sep 19 2019, 12:18 PM
Jacques Lucke (JacquesLucke) edited projects, added Cycles, BF Blender; removed Add-ons (Community).
Philipp Oeser (lichtwerk) added a subscriber: Philipp Oeser (lichtwerk).Sep 19 2019, 12:32 PM

Can confirm.

T70064.blend544 KBDownload

tom k (tomjk) added a subscriber: tom k (tomjk).EditedSep 19 2019, 12:33 PM

Example file:

colorNodeMuteIssue.blend92 KBDownload

Looks to affect pretty much any node that has colour or colour-like (i.e. vector) inputs and non-colour output.

edit: Apologies, does not affect normal map and vector displacement (muting pulls value from a different input).

Jacques Lucke (JacquesLucke) added subscribers: Clément Foucault (fclem), Brecht Van Lommel (brecht), Jacques Lucke (JacquesLucke).Sep 19 2019, 12:35 PM

Ah, actually, I'm not sure if this is a bug in eevee or Cycles. Although, the eevee solution seems more useful.

Consider this setup:

Cycles replaces the internal link with a convert node that converts the Color input to the Value output. This happens to work the same as RGB to BW apparently.
However, eevee does this:


So it does not convert the color to an intermediate BW value.

I still consider this a bug, because Cycles and eevee should work the same in this regard.
@Brecht Van Lommel (brecht), @Clément Foucault (fclem) should Cycles or eevee be changed here?

Brecht Van Lommel (brecht) closed this task as a duplicate of T54777: Some Cycles nodes are active when muted (RGB To BW, Math, vector Math, Separate RGB).Sep 19 2019, 2:30 PM