GI Second bounce

[percydaman]

Hey I think I found a way to extract just the secondary bounces from on image. If this is overly obvious or theres a better easier way to do this then disregard.

I rendered an image with my secondary bounces multiplier set how I like. then rendered same image but set secondary bounce multiplier to 0. Took both images into photoshop and set both image onto layers and set layer type to difference. Saved that image. Thats the secondary bounces. If I take that image and layer it on top of the image with no seconday bounce and set layer type to linear dodge, it appears to be the same image. You can then adjust the secondary bounce images brightness and so on.

Anyhoo, didn't see a secondary bounce render element in the vray buffer so there ya go.

percy

[jacksc02]

very interesting, would you mind showing an image or 2 or the passes and the final output?

Cheers
Chris Jackson
cj@arcad.co.nz
www.arcad.co.nz

[cocolas]

cool.

thanks for sharing, percy.
if you could show some pics of it...


paul.

[percydaman]

sure okay so first render your image with both bounce multipliers where you want. Here it was default 1.0 for first and 1.0 for second




then set second bounce to 0.0 and rerender:



take both images into photoshop. copy and paste firstbounceonly.tga onto bothbounces.tga and set layer type to difference. you will get this which is named secondbounceonly.tga



okay then, take secondbounceonly.tga and copy and paste it onto firstbounceonly.tga. If you set the layer type to linear dodge, it will look the same as the original image rendered with both bounce settings at 1.0

Having established that, You can go to the secondbounceonly layer and adjust it for brightness and such. Hope it explains.

[percydaman]

okay actually if you attempt to adjust the lighting/contrast or whatever of the secondbounce layer, it will look the same if you had just did the same operation with the image showing both bounces. So maybe its no good. Anyone else want to weigh in be my guest.