SOLUTION: Install Blender using the .msi installer, not via the .zip download. This works for 2.79b official, but I have not yet tried using the most recent Blender 2.79 build.
So do volumetrics in Cycles not work with OpenCL or what?
I just bought a Radeon RX580, upgrading from a GeForce GTX560 Ti … Running Win 7 Pro 64-bit
In the official 2.79b, I create a cube then apply a simple volumetric scatter material to it. Renders fine with CPU, but when I try to render with GPU I just get a black box. This is in the viewport.
In both 2.8 and the most recent build of 2.79, when I do exactly the same thing, the render (viewport) hangs on sample 1. Sometimes I can go back to Shaded mode, other times Blender goes into “Not Responding” and I have to shut it down via the Task Manager.
I also just now tried doing an actual render, rather than just viewport rendered mode, using the most recent 2.79 build. I initially had it set to use both CPU and GPU, and it did indeed start rendering. However, only the tiles being rendered by CPU were actually rendering. I then went in and turned off CPU/GPU combined rendering, leaving only GPU on. When I again tried to render, it hangs up immediately: 0/40 samples. (EDIT: Correction. It did eventually finish one tile. It also told me the estimated render time is like 16 hrs. Which is insane seeing how the CPU can render it in like a minute or so)
No errors or anything unusual in the console.
This is very disappointing, as volumetrics is one reason I wanted to upgrade my GPU, and it worked just fine with my old GTX560 Ti