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Attribute node does not work in Cycles when referencing a Vertex Color named "color"
Confirmed, NormalPublicBUG

Description

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: Radeon (TM) RX 480 Graphics ATI Technologies Inc. 4.5.14760 Core Profile Context 20.45.37.01 27.20.14537.1001

Blender Version
Broken: 2.79 - 2.93.0 Alpha, branch: master, commit date: 2021-04-14 02:19, hash: rB6776b74d0a67
Worked: Never?

Short description of error
In Cycles, the Attribute node always returns black when the attribute name is "color".
The color attribute can be a common Vertex Color or created through Geometry Nodes.

Exact steps for others to reproduce the error

  • Open attached file
  • Display render preview (note that the object is black)
  • Change the name on the node attribute and Vertex Color to "color2"

Now the node attribute works

Event Timeline

Germano Cavalcante (mano-wii) changed the task status from Needs Triage to Confirmed.Apr 14 2021, 4:37 PM
Germano Cavalcante (mano-wii) changed the subtype of this task from "Report" to "Bug".

I just wanted to clarify that this is not limited to vertex colors. Thanks to a recently added feature, custom attributes created in geometry nodes can be used directly in Cycles without the need for vertex colors: https://developer.blender.org/rB3a6d6299d
Maybe the fix will apply to GN as well, but I think it would be good if you could modify the name or description of this task to indicate that it also affects geometry nodes, since you closed my task.