to keep diffuse property of a material constant

[jdomingo]

Hi

Is there a way to keep the diffuse of a material constant no matter how you change the light intensity?
Or maybe if you change the light intensity the diffuse property of the material will adjust inversely so it will not get blown out when setting the light to high intensity?
What happen is when i change the light intensity to higher value, i have to change each material diffuse property to get that balance of light and shade. changing each material is frustrating.
Is there a way to achieve this in nodes?
How about using the physky with the light turn off?

thanks

[Janusz Biela]

Hi

Is there a way to keep the diffuse of a material constant no matter how you change the light intensity?
Or maybe if you change the light intensity the diffuse property of the material will adjust inversely so it will not get blown out when setting the light to high intensity?
What happen is when i change the light intensity to higher value, i have to change each material diffuse property to get that balance of light and shade. changing each material is frustrating.Is there a way to achieve this in nodes?

This part is easy: You should keep physical behaviour of surfaces.
So white wall 80-90% diffuse, darker surfaces (wood, plastic dark) around 60-70%.
If Kray has Global Illumination compatible with real world (I mean mathematical formula) so why we don`t try keep also surfaces as real?
If you have over bright areas this mean too strong light or bad setup surfaces or...bad tonemaping. Kray just shot and render photons..rest job is yours
We must remember : human eye has ideal tonemap, why we see difference between real world and clean renders (without tonemping - try LINEAR in Kray...) . why we must use tonemapers.
So for me is clean: Diffuse for bright materials 80-90%, for dark minimum 50-60%.
Some material must have fresnel (I do it from standard LW setup) this is important becouse for example ceramic vase without fresnel look a bit strange and "flat" (around border of object should be high reflection in center of view camera very small reflection with visible only windows... http://ny-image3.etsy.com/il_fullxfull.148545863.jpg )

How about using the physky with the light turn off?

thanks

Of coarse (in V-ray render people do that often because for exteriors is very hard render with phisky and Sun...is better control without, renders looks as from HDRi with good radiation everywhere, but of coarse a bit strange)

[jdomingo]

thanks Johny for your answer. Ok, let us say I already have preset material with, as you said, bright material with 80-90% diffuse property and dark with 50-60%. Now, if I have another project which require brighter sun or light and I use my preset material (mentioned above), somehow the material get overbright. then the painful part i have to adjust each material with accordance with the new light set up. Can I just adjust the light without adjusting the material diffuse property? If only Im a master of node and i believe with nodes it can be done. something like "if and then" thing. example..
if the sun is = 1, then diffuse is 80 or 90 or 50 or 60
if the sun is > 1, then diffuse (adjust automatically by lesser value)
if the sun is <1, then diffuse (adjust to higher value)

something like this.....

thanks again

[Janusz Biela]

...just show render with problem

[jure]

Hi

What happen is when i change the light intensity to higher value, i have to change each material diffuse property to get that balance of light and shade. changing each material is frustrating.
Is there a way to achieve this in nodes?
How about using the physky with the light turn off?

thanks

There is no easy way to do this AFAIK. But why do you change light intensity at the first place?

[jdomingo]

@johny

sorry johny i cant show the project now for it's under strict confidentiality, i will test a simple box scene with what im trying to ask about. thanks

@jure

well some doesnt like dark looking image some want it really bright and that how a adjust my work with accordance with my superior's taste.

or is it possible KRAY has its own camera type like in vray, where you can adjust setting like in real camera? that would be great.

thanks guys

[Janusz Biela]

or is it possible KRAY has its own camera type like in vray, where you can adjust setting like in real camera? that would be great.

thanks guys

I think G. write in code REAL TIME exposure for that...so You will not need "V-ray camera" But this need a bit time.....coding You know not easy bread...
btw
I toked last time with Jure about DIFFUSE and we think is also good idea just keep diffuse 100% (default) . When material has reflection 10% we reduce diffuse to 90%.
I test now this idea. Maybe good idea. Kray has in code part which reduce power from photons depends from color. So when is dark floor photons very fast loss power. I use personally recurse 10 maximum so if room is total white (100%) photons does not die to until 10 bounce (of coarse some escape by window) This is not correct model, because white walls are not ideal white so color must by a bit gray...so Photons loss a bit energy after reflect.

[jure]

@jure

well some doesnt like dark looking image some want it really bright and that how a adjust my work with accordance with my superior's taste.

or is it possible KRAY has its own camera type like in vray, where you can adjust setting like in real camera? that would be great.

thanks guys

You can use exposure in Kray general tab to change brightness of your image. But most of all what you want to use is tonemap blending controls. You can get various effects with those controls - from very dark to truly bright images without changing your light or surface setup.