Glossiness and Roughness effect not same

[jackieteh]

Hi,

I have read some articles about how to convert the Glossiness map to the Roughness map, all the article mention it is simple, simply invert them in photoshop, so I give it a try.

For Glossiness map:

1. Open a wood image which I download from the internet in Photoshop
2. Desaturate the wood image and save it as a Glossiness map
3. And apply it to the plane which I created in 3ds max, and click render.
4. The final render looks like the image with the name"glossiness.jpg"

For the Roughness map:

1. go back to photoshop and invert the glossiness map which I created in the previous first step.
2. and then replace the Glossiness map with the Roughness map in 3ds max
3. check the " Use roughness" option in VrayMtl, hit render
4. The final render looks like the image with the name "roughness.jpg"

the two results look different, am I missing any step? or is this a bug in V-Ray 6?

[Pixelcon]

looks like the map isn't actually inverted or not linked properly. Post a scene?

[hermit.crab]

The described steps are correct - the issue must lie somewhere else. Try inverting the bitmap through the "Invert" option in the VRayBitmap options.

[jackieteh]

The described steps are correct - the issue must lie somewhere else. Try inverting the bitmap through the "Invert" option in the VRayBitmap options.

Yes, inverting in the "invert" option in VRayBitmap options get the same result. Is this means we cannot invert the map in photoshop?

[Vizioen]

I had this problem in the past too and I couldn't figure out why, so I stayed with glossiness rather than roughness. But I tested this again. The matter of the fact is that bitmaps for reflections, glossiness, etc (all 0 to 1 data textures) need to be loaded with color space transfer function set to none or inverse gamma needs to be set to 1 (if wrong please someone correct me).

So make sure if you test this out again, that in both cases you need to set gamma to 1. In my tests this seems to be consistent.

edit: To Chaos, might be nice that if you drag out a bitmap or assign one in one of the slots that are actually data maps this is automatically set to 1, unless I'm missing something.

[hermit.crab]

jackieteh Try Vizioen's suggestion.

To Chaos, might be nice that if you drag out a bitmap or assign one in one of the slots that are actually data maps this is automatically set to 1, unless I'm missing something.

This is already a thing. It works by appending the colorspace to the filename and setting the transfer function type to Auto.

[jackieteh]

jackieteh Try Vizioen's suggestion.



This is already a thing. It works by appending the colorspace to the filename and setting the transfer function type to Auto.

Mine is set to "Auto"

[^Lele^]

"Auto" has limitations, such as instanced maps.
Ensure they are in fact unique, and manually set the gamma to 1 (or raw, whichever you prefer).
It'd all go much quicker if you shared the files, though.

[jackieteh]

"Auto" has limitations, such as instanced maps.
Ensure they are in fact unique, and manually set the gamma to 1 (or raw, whichever you prefer).
It'd all go much quicker if you shared the files, though.

I cannot share the file due to client policy, sorry

If I facing the same problem with my freelance job, i will share it to you.