Bump map not working properly (VRayMtl + Bump BRDF)

[enrique.monzo]

I am playing with the next scene (cube with UV and VRay infinite plane) and material setup for the cube (VRayMtl + Bump BRDF):



The bump map is a color JPG image used on the UVW unwrapped cube:



I observe the next issues:

1. The only control that modifies the bump effect is the Bump Amount Texture field in the Bump BRDF node --> The bump ffect is observable in the range from 0.001 to 1... greater than 1 is always almost the same
2. Bump Texture Bump doesn't affect at all --> Changing the value from 100% to 0% gives always the same result.


Renders as follows:



Bump Texture Bump = 100%; Bump Amount Texture = 1.0




Bump Texture Bump = 0%; Bump Amount Texture = 1.0



Bump Texture Bump = 100%; Bump Amount Texture = 100.0

[poseidon4o]

Can you please upload the scene?

[enrique.monzo]

Hi poseidon4o, you find attached a ZIP file containing the .blend file and the bump map in PNG

bump_test.zip

[poseidon4o]

enrique.monzo can you test with latest nightly, both "Bump Texture Mult" and "Bump Amount Tex" should start working.

[enrique.monzo]

poseidon4o I tried with the latest build vrayblender35-2.79-a90e63f-x86_64-windows. You find as follows my observations:

* Bump Texture Mult.: the bump effect seems now to decrease with the value, dissapearing completely then it reaches zero. But it seems not to be linear variation. From 100% to 25%, the bump effect is almost the same, and it is only appreciable from 10% down to 0%
* Bump Amount Textur: exactly the same behavior as Bump Texture Mult.


Questions:
- Is this non-linear behavior the expected one in both parameters?


As follows, snapshots of the render for Bump Texture Mult values from 100% to 0%.

Bump Texture Mult = 100%


Bump Texture Mult = 50% (not appreciable variation when it is expected to be half)


Bump Texture Mult = 25% (not appreciable yet, and it should be 1/4)


Bump Texture Mult = 10% (appreciable effect)


Bump Texture Mult = 5% (appreciable effect, but too much for being 5%)


Bump Texture Mult = 0% (the bump effect is not present anymore, as expected)