I’ve been sketching out a node-based clouds shader, but at some point, it started rendering with these ugly rings that almost look like a repeating circular gradient, or banding around wherever the camera is. Not the camera object, but the actual viewport camera. Any idea what is going on here, and/or how I solve it?
EDIT: This is Blender 2.92, by the way, running on Linux with an RTX Nvidia card and drivers.
If you’re in Eevee, for performance reasons volumetrics are only rendered within some limits. Check Render > Volumetrics > Start/End values. For Cycles there shouldn’t be a problem. You may also want to adjust the camera’s clip start (press N in viewport, then go to View > Clip Start/End).
Sorry, I forgot to say that this is Cycles, but it is not a clipping issue, because it repeats, is circular, and I can see past it.
The boarder of each circle also softens when I enable clamping on the last math node before the input to the principled volume sharder’s density. So there might be something with the node tree, but I never use the camera’s position, or window texture coordinates for anything, so I have no reason to believe this is anything other than a bug or some sort of overflow issue, where the numbers get so high that they loop back around? But why is that dependent on the camera’s point of view? Seems like some sort of optimization thing that I’d want to turn off, or work around.
Hard to say without more info, it would be more helpful if you can post the blender file or at least a picture with your volumetric shader. But if you say clipping is fine, then yeah, a math issue is most likely. You can also check that Render Properties > Cycles > Light Paths > Volume has enough bounces (default is 0, try at least 1).
I just checked it on Windows and it seems fine here… So maybe this is a bug on the Linux version?
And, here’s the node tree
Aaaand here’s a file with the shader in it
only cloud shader for debug stufferinos.blend (941.2 KB)
Works fine for me, I’m using Windows. It must be either a Blender bug in Linux or most likely a problem with your Linux video drivers.
