There are two windows in that little room (one on the wall just above the stairs and one on the far end of that back room… not to mention the stair opening itself). There is no way that room should be so dark … I think the Maxwell result is more correct … how is it possible to avoid this pitfall in Vray ?
I don’t think black or white points or a curves adjustment would do it. Also, when I put portals in all windows the problem is still there. It can only be remedied if portals are assigned different multiplier values (but that would be totally unacceptable in my book)
It is related to the gamma setting… Maxwell uses a 2.2 gamma correction by default (not in a post effect, but in the renderer itsself). You can do this in vray by using gamma color mapping, with bright set to 0.455 (=1/2.2). But your materials will be washed out, because you created them with a gamma 1.0. So we need a gamma correction for colors and mat previews etc… This is being considered already.
In max this is perfectly possible because there you have a display gamma control, and you can control textures by using the color correct plugin.
Your vray forum link doesn’t work. But here are some links on the gamma topic, or what it is called: working linear space workflow
It is related to the gamma setting… Maxwell uses a 2.2 gamma correction by default (not in a post effect, but in the renderer itsself). You can do this in vray by using gamma color mapping, with bright set to 0.455 (=1/2.2). But your materials will be washed out, because you created them with a gamma 1.0. So we need a gamma correction for colors and mat previews etc… This is being considered already.
I see, so it is a problem of some sort, but it is being looked into … Good to know
I will take a look in the links you provided. Thank You !
I don’t know why the back room is darker in their images… in my rendering below it appears a bit brighter… don’t mind the colors, they don’t match the maxwell rendering.
Hey Vlado, I was testing this too, but I can’t open the max file to see their light values. What are the direct light and skylight multipliers and colors? And the diffuse for the walls? In my test, the back room is also lighter, and with gamma correction it seriously lacks contrast, I’m not so sure anymore if it is really the way to go.
Note that I use gamma color mapping! All materials are adjusted for that purpose. If you look at the wall material, you may think it has a very dark diffuse but in fact it is not, because you should see this with a gamma curve 2.2 applied (which is not possible right now in rhino). Follow the links I posted before for more info about gamma correction and why we are working in a wrong way for years now. I’m really bad at explaining all this. Especially gijs’ tutorial explains the starting problem very well.
I see no blotches, but If you want ultra smooth GI increase the hsph value to 75 (it is 60 now).
hmm, I do not think it is just a gamma issue. I think there is a falloff issue as well. Somehow light does not appear to have enough bounces. There should be some glow entering the top window and hitting the back wall. In Vray, that back wall shows no signs of ambient light from the top window.
In the scene that I have, the light is positioned in such a way that no direct light comes through the top window (it’s in shadow). So I’m not sure where maxwell gets it from…
Hey thomas, I think my example pretty much is the same as maxwell. I had to guess how the sun was positioned, and I alsi had to guess the light values and colors (balance between sun/sky). I think with exactly same balance, the result will be the same. As you can see, in maxwell example the sun is stronger, that’s where the difference comes from imo. I will try an example with darker sky and brighter sun.
Here it is, pretty high quality settings for ir map and LC. I used now a ratio of 10/1 for strength of sun/sky, which was too much because now my overall image is brighter than maxwells. I wonder what kind of lights they used in the maxwell test. Does maxwell have a linear falloff light type? Or was this done with sun/sky system?
Well, in nature there one way that light travels (in the “air” medium; given normal turbidity and ozone levels), so Maxwell light is handled automatically internally… so to answer your question, no there is no need for falloff types (it is fully automated).
Also, no this was not done with physical sky because the shadows are wrong (non parallel). The guy just used that little sphere above the three windows.
Ah ok, if someone can figure out the ratio bewteen sky strength and sun strength, please tell me. Also the diffuse color of the grey walls, which is very crucial in this scene…
Is the scene rendered in Maxwell from Max or Rhino? Are you rendering that scene in Maxwell with Physical Sky and with Sunlight enabled?
Regards,
Corey
Reading helps…“Also, no this was not done with physical sky because the shadows are wrong (non parallel). The guy just used that little sphere above the three windows.”
