VRay Next: PBR material - result not as expected

[la812]

Hi all,

I have only recently discovered PBR material for metals in VRay Next for Rhino and would need to use it for a project now.
I downloaded maps from textures.com to compile a brass material.

I attached a screenshot of the maps and the result of the compiled material as shown on textures.com as well as what I get as a preview in the asset editor.

I loaded the albedo map into the Color slot, the metallic map into the Metalness slot, the roughness map into the Roughness slot and I added a Bump slot where I set the Mode to Normal Map and loaded the normal map.

The result is not even close to what is shown on textures.com - so I was wondering whether I have to change the values of the respective slots (which has not helped much so far) or if I have to change any other settings to get closer to what I want to achieve.

My material is very glossy and reflective compared to what I expected.

I am trying to understand how PBR works, so I would be thankful for any hints.

Thank you in advance!

[seltzdesign]

Funny, I just had the same question, found your post and realized its for an almost identical material as well (worn brass).

What I found is that switching the textures' Color Space from Screen Space (RBG) to Rendering Space (Linear) totally changed how the material looks.

Take a look at what my material looks like after just adding all the textures:



Looks just like your example.

Now with all textures (except the diffuse color map) to linear:



That's more like it. Click on a texture and change the color space there:



I have no idea why it happens. Only thing I can assume is that other 3D software uses linear as standard and Rhino - notoriously NOT made for 3D rendering - just defaults to RGB. Basically everything should always be in Linear Color Space until the very last moment.

Hope that helps.

[Peter.Chaushev]

You've correctly solved this.
As mentioned in https://docs.chaosgroup.com/display/...BR#PBR-VRayPBR the Metalness and Roughness slots require the slotted TexBitmaps to be set to linear color space. Same applies for the Normal map slot in the Bump section.

[la812]

Thank you both for your reply and explanation!