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Smoke Colour from flow source in Cycles differs from colour set and viewport colour.
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System Information
Ubuntu 15.10 x64 Geforce 580 GTX

Blender Version
Broken: 2.77 official, 2,76b official, 2.75a official

Short description of error
When setting a smoke color in the flow source, the color fetched from the Cycles attribute node is off quite a bit. This might have been the source for the problems artifical3d had with smoke colors in the gooseberry tornado. While the openGL viewport shows the colour correctly, the problem also appears with BI render.

Here you see a comparison of renders with different shaders using the colour from the attribute node and the same colour set directly in the shader:

Viewport OpenGL render:

Volume Scatter + Volume Absorption using colour from attribute node:

Volume Scatter + Volume Absorption with colour set directly in the shader nodes:

Emission using colour from attribute node:

Emission with colour set directly in the shader node:

Exact steps for others to reproduce the error

Bake the sim of the attached file. Connect different shaders in the network with and without taking the color from the attribute node. The color set in the nodes is the same colour as the one set in the smoke flow source.



Event Timeline

Gottfried Hofmann (gottfried) raised the priority of this task from to Needs Triage by Developer.

heres a file that gives the exact same result (division by density and srgb to linear)

Sergey Sharybin (sergey) triaged this task as Confirmed, Medium priority.
Sergey Sharybin (sergey) closed this task as Archived.Apr 12 2016, 1:32 PM

This is how color space was working forever, and it's not trivial to solve it without intorucing regressions.

Here's a working patch for this D1897, but it needs more testing. Please go ahead and help us testing it making sure it works all solid.

Original issue i'd just consider known breakage and consider a TODO.