Luminosity study

[NiGMa]

Hi guys, did some playing yesterday, I discovered a few things that helped me better understand this complicated (BUT AWESOME!) renderer.

kray notes:

-"photon mapping" as opposed to "light mapping" does not take into account backdrop/textured environment, etc.
-"limitdr" = "exposure" when output format is set to LDR
-postprocess autoexp,.5; is awesome!!
-glass should never have any diffuse, using any value of diffuse slows rendering considerably, to achieve colouring, use reflection highlight to max, then if more colour still need used color filter.
-lights that end up getting calculated with "direct" cannot be cached so they are bad for animations
-area lights should always be converted to luminosity lights under the "quality" tab, this way there is less things to control and uniform noise, plus again, it can be cached in an animation so long as luminosity lights are set to "indirect"
-"direct" quality lights can be achieved with "indirect" mode if low spatial tolerance is used
-photon count doesn't seem to have an effect on "direct" lights but does seem to on "indirect" lights
-the "Luminosity threshold", "Rays min" and "max" settings on the "Quality" tab has no affect on "indirect" lights, I guess it only controls "direct" lights
-"Precache blur" on the "Photons" tab can sometimes cause light leaks, set to 0%
-"Spotlights to area" on the "Quality" tab only works on spotlights that have "Intesity Falloff" set to "Inverse Distance ^ 2"
-"Spotlights to area" on the "Quality" tab also works as it should when "Area lights" is set to "Computer with Luminosity" or "Computer separately (adaptive sampling)"

This is a scene I made similar to SilverLW's.
http://www.koscad.com.au/pete/lumilights_01.avi

[silverlw]

Wow alot of tips here and it seems youve got the hang of it
Could you elaborate more about : "-postprocess autoexp,.5; is awesome!!" ?

[NiGMa]

Could you elaborate more about : "-postprocess autoexp,.5; is awesome!!" ?

For my jobs, I need alot of camera shots that go from outside the house around the pool, etc, and then inside, I think what "autoexp" will do is what camcorders do, that is, change the aperture, shutter speed, so that the amount of light is good, not overblown, and not too dark.

From a short test of it, it seems to do it! I'll wait for a good job to try it on though.

I just saw it in the manual.

[NiGMa]

By the way, what that video is showing off is that all those luminous polys, plus the area light, are all behaving as indirect lights, but the spatial tolerance is set to a VERY LOW value of 0.01!!! so the quality is good, but since its cached it only makes the first frame slow.

Notice that I set the luminosity min to 5000! thats because none of the lights are direct, and so its not actually affecting my scene. I could make it 5,000,000,000 and it wouldn't matter. =)

[Captain Obvious]

-"photon mapping" as opposed to "light mapping" does not take into account backdrop/textured environment, etc.

This is not a bug. Photon mapping simply does not work with backdrop illumination.

-glass should never have any diffuse, using any value of diffuse slows rendering considerably, to achieve colouring, use reflection highlight to max, then if more colour still need used color filter.

This is true for ANY renderer. Coloured glass has color filtering, nothing else. That's how it works.

-area lights should always be converted to luminosity lights under the "quality" tab, this way there is less things to control and uniform noise, plus again, it can be cached in an animation so long as luminosity lights are set to "indirect"

Caching for animation only works if nothing is moving but the camera, so it's not something you should always be doing.

-the "Luminosity threshold", "Rays min" and "max" settings on the "Quality" tab has no affect on "indirect" lights, I guess it only controls "direct" lights

That's right.

-"Spotlights to area" on the "Quality" tab only works on spotlights that have "Intesity Falloff" set to "Inverse Distance ^ 2"

Lights in Kray should ALWAYS have inverse square falloff. Always.

[NiGMa]

The notes were to myself, I just thought I'd post them here as well.

Thanks for the input guys