Bump shader value having no effect in CUDA hybrid RT render

[seandunderdale]

Ive been working in CUDA hybrid mode lately and Ive been shading up car interiors. For extra layered detail Id often (in cpu mode) drop a leather texture into a bump slot of a Vray Mat and then drop that shader into a bump node to give it some subtle breakup. Ive been experiencing in GPU mode that the bump shader value does not respond, and only the bump value of the shader that it has as its input, had any effect over the bump value. I can set the bump shader value to 10 or 0, it doesnt seem to change anything.

I had this issue on my current job, and got around it by using remapHSV nodes for the bump maps going into the bump shader. That way I could still control the value of the bump shader.

Ive attached a scene to show what I mean. Everything is fine in CPU mode, the issue only happens to me in GPU CUDA.

Maya 2018.6
Vray 4.30.01

[seandunderdale]

I had a colleague of mine test this and was able to reproduce it. Any word on if this is a mistake in how Im using this? Or if its a bug?

[yolov]

Sorry for the delay, we'll have a look and get back to you.

[Zdravko.Keremidchiev]

This seems to be an issue with the bump multiplier on the GPU and the combination of two bump maps. I logged it under this ID VGPU-4794

[seandunderdale]

Hey guys. Is there likely to be a solution to this issue in the next week or so? We will be starting to a new car job soon so lots of interior prep of plastics, leathers and fabrics, some of which will be using this bump shader setup.

[Zdravko.Keremidchiev]

We are still working on it. I'll get back to you shortly.