Hello Lele
I would like to thank you for the very good tutorial.
You explained a lot of stuff for me.
I havea question about the vra sky..
it is still only .5 in the color float , is there a way for getting it up to around 1.0 and still have the same predictable results? or it dosn’t matter that it is still around .5
gili
Hello Gili and thanks for the kind words 
In reality the tutorials isn’t “correct”.
It only shows a mean to an end.
Feel free to ddarken the colours further,and raise the ISOs (or lower F-number, or raise exposure time) to get a brighter sky in outdoors, if you so desire
The script to mass darken materials and maps has spinners to allow for a different number than 0.255 as RGB output level, so to leave freedom to the user.
Have a Merry Christmas and a happy new year, you all!
Lele
Thank you so much for the tutorial.
Regarding the script, when I use a mask material on diffuse slot, the script changes it to vraycolor material. Is there a way to fix that?
Best Regards..
Hi Lele,
today I have seen video tut 3. My english is not so good, and hearing english is difficult to understand. Maybe you could explain the 0.255 method in some words here.
My thoughts:
- physical correct the brightest real life white reflect max. 80% of the light
- if we use 255, than we set 100% reflectance and this is not physical correct. Light between white surfaces bounce to much from one surface to the other. This cause flat lighting at interior renderings.
- a correction is necessary
- if we set 0.255, than the brightest white reflect only 25% of the incoming light - dosn’t seems to be physical correct. This cause, that indirect light bounce much less than in reality. Side effect: render times are lower and less GI noise. I suppose, interior renderings will show to dark shadowed areas.
- if we set all color at 25%, than the relation between white and heaven environment is changed to. OK, we get a darker background, but this not physical correct again.
So, what are the problems we have:
(1) white should reflect 80% only
(2) the environment should be visible in the background
(1) here is a 0.8 multiplier physical correct
(2) The human eye dosn’t work linear. If I right informed, it work expontial. The same for classial film material. Cheap old CCD cameras work approx. linaer and catch low contrast only. So, if we like to catch high contrasts, than an expontial color mapping is recommended. The “Reinhard” mapping do a great job here, the user can shift between linear (burn 1) and exponetial (burn 0). Burn 0.6…0.8 is a good start point.
Also, I’m not sure how 3DSmax handle it, so far I know, Vray works internal linear. If we are seeing renderings ot computer screens, than a gamma correction of ~2.2 for output is necessary. If we don’t do it, than the contrast of lighting is to strong.
I have used Maxwell Beta for a long time: my experience for photoreal images is:
- don’t use white colors brighter than 80% (each RGB channel should be below 80%)
- use gamma 2.2 output (vray user must manual correct input color/textures with gamma 1/2.2=0.4545 - Maxwell user get it per default)
- use the burn value to catch high contrasts
Merry christmas,
Micha
PS: Maxwell seems to use an internal correction for 100% white colors, so to much GI bounces are avoided per default.
Will check the mask material.
There are some inconsistencies in the maxscript side, so i’ll try and cater for that type of map as well.
Lele
cheers for the tute and info Lele…go have some beer and enjoy chrimbo mate
Hey Micha!
The tutorial has no pretense to be “physically correct” (read the post above.)
We have no brdf/bsdf implemented in vray (yet? ), so mine is an empirical method to get the exterior shot in range ( i implicitly consider sun and sky at a value of 1 o be “correct” and expose the camera and materials to it).
I am not sure about the reflectance values you state (namely white being 80% reflective).
Reading here , for instance, seems to be closer to what the empirical method and the proposed workflow suggested:
These spheres have an albedo (in other words, “The proportion of incoming light reflected”) of 0.1-0.3-0.1 in RGB for a “dark” green colour.
Under these circumstances, a much whiter material may be around 0.3-0.5 in all of them.
Of course, it’s scaled down to 8bit, so there may be three ways to produce a white rendered pixel: brighten the material, brighten the lighting (like in the case of the picture above from the top to the bottom row), raise exposure.
Perception matters here, as we end up displaying on 8 bit devices.
As for gamma, LWF et al, i think a lot has been written, and i’d rather not get back into it ( i still smell smoke from past flames, lol).
I use gamma in my tutorial to brighten darker ares, as that’s what a gamma curve does to pixels.
I could have saved an HDR image and have done that in post.
A sidekick of darkening materials is that you gain contrast, brighten them, and you lose it.
Hope i clarified bits, and i know i skimped on others.
We’ll talk again about this after the holidays, anyways 
Lele
Eheh, just had one wild nite yesterday.
It’ll last me until at least new year
I’m getting definitely older by the day (duh!)
Lele
I would love to see the video, but I’m having troubles to run it. I can hear the voice, but I am not able to see anything. What king of codes are you using?
Same problem here. Audio but no video.
get vlc, plays everything 
btw, thanks for the videos studioDIM.
Olli
The one needed is the TechSmith codec, and you can find it @ http://download.techsmith.com/tscc/tscc.exe
Audio is in mp3.
I’m humbled hearing you liked the tutorial
Lele
Still to this day im suprised just how many people dont know about that codec.
p.s. writing this on my 30" dell LCD hehehe
I’m SO glad you stopped calling it my ‘30" beast’, mate…
Father Christmas is as well, his honour saved :lol:
Merry Chrimbo!
Lele
I read this post and for me the only problem is the VraySky. It seems to dark in comparsion with the whole image, when a VrayCam is used and everything else appears correct.
I have my own workaround.
I setup the scene and use the power of the VrayCam and its options. when everything is lit well, excepting the Sky, then I put an outputmap to the Sky. now the problem is the Sky. It puts some more light to the scene and the image has a blueish tint. to correct this I tint the “white balance” in the VrayCam rollout with a blue color out of the rendered image to compensate the blueish tint. and volià!
I am not a fan of correcting all the colors, when the only problem is the Sky. If I could make a wish, it would be nice to have an option to multiply the brightness of the sky but not its GI. I think the problem is the VraySky, it’s “only” a map and it’s also acting like that.
here is a rendered image.
…and here is the scene. you must have max8 and vray 1.5 rc3
http://www.pixelschmiede.ch/chaos/settings\_daylight\_vraysun.zip
I don’t know if it’s physical correct, but for me it’s good enough.
I ask me how maxwell handles this?
best regards
themaxxer
Yeah :lol: also my GF is not sure WHAT to think now :lol:
Hey maxxer, surely enough, it’s one of the options i covered in the tut (darkening the sun multiplier darkens the sun as well; using an output map in the background slot does the trick too, even though i cover that when we have a white BG, rather than the sky), but we part from phisical-like behaviour from the materials, as well as bending what the Sky and Sun are supposed to do.
What i propose is to stop thinking in 8 bits: that is the heritage of old CG, not the new sun, sky and camera :).
Maxwell is a closed system (it doesn’t work with anything else than its own materials and cameras), hence it’s a lot easier for them to automatically bring things into range.
Try the same render of yours as is, and with darkened colours plus gamma, and see what happens to rendertimes, and white dots
Lele
yeah!
i double that! it seems a smarter way of exposing rather than mess up within the relations (physically correct) between the sun+sky+camera!
How is all this affected if I don’t use the VRAY frame buffer and just use the MAX buffer? I modified my MAX gamma and lut settings to 2.2 with affect color and material editor set to on. I also have my bitmap input gamma set to 2.2. I am not getting the same kind of results Lele?
Best regards,
Dave Vaughn
In that case, using the colormapping settings will apply the 2.2 gamma twice.
You can leave the VRay colormapping gamma at 1 if you use the max VFB and the max gamma is set to 2.2 (or the other way around )
Regards,
Lele