linear vs SRGB materials - which to use?

[afecelis]

Hi guys,

Setting up the materials I noticed that the ones using an image file have 2 options for the color space, one of them for the v-ray settings. If I set that one to linear, the material preview immediately updates and displays a washed-out version. According to this tutorial:
http://www.aversis.be/tutorials/vray...orkflow_01.htm

this is expected to happen when working with gamma 2.2 and having the textures double corrected. I rendered the following image with both linear/srgb material color spaces:

SRGB:


Linear:


From what I've read the idea is that materials look the closest to their original bitmap images. My question is: When we setup the material to linear in the V-ray options, are we double-correcting it? (hence the washed out material preview/render). Is blender already setup to work with a gamma value of 2.2 in combination with Vray? (like 3ds max-Vray work) Should we stick to SRGB for materials?

thanks!

regards,
Alvaro

[andybot_cg]

I use srgb for all bitmaps in color nodes except for hdr images. I use linear for things like alpha and bump maps. For hdrs I'll use gamma correct to adjust the sun intensity a la Peter Guthrie. I only adjust the vray section of the color mapping options. I'm assuming that's correct, but would be glad to have that confirmed.

[afecelis]

Thank you Andy, as usual your experience is most valuable.
Indeed it's a very interesting topic that shouldn't be taken lightly. V-ray's level of control of the render is amazing and there are so many ins and outs to learn. I wonder if you really get to control each and every one of them.

So far, the following image summarizes the state of my learning process:


I know there's still a long way to go, but I'm so happy with everything I've learned. Thanks to everyone

regards,
Alvaro

[andybot_cg]

Glad to help! You're making great strides, this interior lighting is looking very good. Are you using sun and domelight combo?

[afecelis]

Yup, in this case I'm using sun+ world environment IBL (plus simple portals on windows). Somehow, from the tests I've run, a world/env IBL bounces more color bleeding inside than the hemi/domelight. I'll try a version with it to see how much it changes. And yup, I'm also very happy with the interior lighting achieved so far. Interiors are so much harder to resolve in terms of lighting, but V-ray does wonders once you start to learn its tricks

One question Andy, why doesn't the sun support a sky model as in 3ds max? It would be interesting to have an option to enable/disable it, or as in max, have a pop up message asking if you want to enable the sky model when you insert a sun light.

regards,

Alvaro

[andybot_cg]

One question Andy, why doesn't the sun support a sky model as in 3ds max? It would be interesting to have an option to enable/disable it, or as in max, have a pop up message asking if you want to enable the sky model when you insert a sun light.

Not sure what you mean. When you use the sun lamp object in Blender, change it from "direct" to "sun" and in the light properties panel the sky model is there. For the dome, just plug in the "sky" texture for the sky lighting. I'm assuming that's what you figured out, but thought I'd share in case you missed something. The node shown is for the dome light, the properties shown is for the sun object.

Edit: portals work fine if you don't check the "invisible" option, my mistake.

[afecelis]

whoah!!!!!!

I hadn't seen all that info on the sun light! lol. I'm going to try it out right away! That "hosek..." is the new sky model available?

Nice!

[chadstevens]

This is what I mentioned in the other post, there is a direct mode and a sun mode, the direct mode is just a light, the sun mode actually comes with an 'environment map' if you want to call it that.

Cheers.

[afecelis]

This is what I mentioned in the other post, there is a direct mode and a sun mode, the direct mode is just a light, the sun mode actually comes with an 'environment map' if you want to call it that.

Cheers.

Thanks Chad, it took me a bit to understand, lol But better late than never.