Volume renders very, very wierd

Hi! So, I just came over this strange phenomenon (probably a bug): whenever I have a volume shader with a very high density value AND a texture of a sort connected to the density input, it renders with a very strange transparency. Picture show it much better than I can explain in words:

No texture connected (and how it should look like)

Texture connected

Note that in both cases shown the density value is uniformally 1. The noise texture in the second picture doesn’t influence the density value. It’s its mere inclusion in the node tree that makes this (bug?) happen.

The file in the examples:
untitled.blend (1.8 MB)

This indeed looks like a bug.
For better understanding remove Color Ramp node.
Then you can plug Math Node with multiply and check that multiplying 1 over different values looks properly.
Only after plugging noise fac to one of the math inputs the shader breaks.

Also if you swap math node to vector math you can see that it is also not working properly.

My take it’s a problem with noise texture or with how data from it is handled.

I’d report this as a bug with removed Color Ramp and added Vector Math Node example (aside from regular Math Node).

The problem appears to go away if you reduce step size to around 0.5.

It’s less pronounce but in my scenario i needed to set step size at 0.2 to make any difference.

Ah, yes, I had the monkey scaled by 10. With a monkey scaled to 1.0 it needs 0.05 or something like that.