[Bf-cycles] max bounces

[Thomas Dinges]

Hi David,
that is weird, I cannot think of a reason for this at the moment.

The way the feature works, is that it checks if the Light Max Bounce 
setting is greater than the current bounce, if that's the case it skips 
evaluating the lamp.
Did you use the Pathtrace or Branched Pathtrace integrator? Also what 
were your global min bounces? If they differed from the global max 
bounces, it might be worth to check again with these 2 values being the 
same.

Thomas

Am 06.11.2014 um 14:00 schrieb David Fenner:
> Hi Thomas, thanks for the commit yesterday, to control bounces per 
> light, very nice!!
>
> Been doing some tests here, and I ran into a very strange scenario:
>
> When I have 3 or more max diffuse bounces in global render settings, 
> reducing per lamp bounces have little to no impact in render times, 
> even if set to 0 bounces. However, when I have only 2 max diffuse 
> bounces in render settings, lowering per lamp bounces have a very big 
> impact on render times, reducing them almost as much as if I lowered 
> global diffuse bounces on the same quantity. It's like there was some 
> sort of threshold at 2 global bounces. For example:
>
> (on a simple diff scene with one lamp)
>
>
> Global Max Diff Bounces = 0
> Lamp bounces                 = 0
> Render Time: 4.7 sec
>
>
> Global Max Diff Bounces = 3
> Lamp bounces                 = 1024
> Render Time: 10 sec
>
>
> Global Max Diff Bounces = 3
> Lamp bounces                 = 0
> Render Time: 9.7 sec   (almost the same as before)
>
>
> Global Max Diff Bounces = 2
> Lamp bounces                 = 2
> Render Time: 8.5 sec      (lower rendertime thanks to one less bounce)
>
>
> Global Max Diff Bounces = 2
> Lamp bounces                 = 0
> Render Time: 4.9 sec       (before it didn't even care, yet for 2 
> bounces and below its almost as there where no global bounces)
>
>
> It's great, with 2 global diff bounces and below the gains of lowering 
> per lamp bounces are almost as big as if lowering global diffuse 
> bounces, so having only a few lights with GI can increase your 
> rendertimes amazingly, however,  with 3 global diff bounces and over 
> there is strangely almost no gain, even when all lamps have 0 bounces.
>
>
>
>
>
>
>
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