Mac OS X 10.6.8
NVIDIA GeForce 320M
- and -
OS X 10.10.2
Intel Iris Pro 1536 MB
Broken: 2.76 48f7dd6
Short description of error
Plugging an Emission Shader into the Volume output has no effect if the scene's background is transparent. The object with the volume emission material renders as transparent, so you see nothing but an empty transparent (checkered) background.
It does display as expected in the Material Preview and in Viewport Render mode.
If you also plug a Mix Shader into the Surface output, and mix a Diffuse (for example) and a Transparent Shader together, emission will be visible (if mixed somewhere between 0 and 1), but only to a limited degree. And once again, the rendered result differs from the Material Preview and Viewport Render.
Exact steps for others to reproduce the error
- Add an object and give it a material with no surface shader, only an Emission Shader plugged into the Volume output.
- Do a test render to verify that it is showing up.
- Enable the Film > Transparent option in the Render Context.
- Render again and find that the object has become invisible.