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View Full Version : compiling render passes ? how ?


everlite
08-25-2006, 10:03 PM
Something i'm a little mythed by, rendering seperate passes and the process by which you recomp them together.

So, say in max, i render the different passes, ie; defuse, specular,shadow etc and so on. How do i then re compile them in the composition program, whether it's photoshop or after effects?

is there a layer order in which they should be placed back down?

I'm sure you switch each layer to a blend mode, but which one? screen? multiply?

Whn i try this, i have trouble trying to get it back to the original single pass render.

Any thoughts or suggestions?

- Dave.

Seraph135
08-26-2006, 04:21 AM
So, say in max, i render the different passes, ie; defuse, specular,shadow etc and so on. How do i then re compile them in the composition program, whether it's photoshop or after effects?

I'm sure you switch each layer to a blend mode, but which one? screen? multiply?

is there a layer order in which they should be placed back down?

Any thoughts or suggestions?

- Dave.

On my website I have a pretty basic tutorial for getting started with rendering passes and compositing them. Its at the top of the tutorials section.

In general you will want to order things from back to front. The furthest away things at the beginning and then layer things on top as they get closer. Sometimes background elements become foreground elements and you have to create mattes to deal with these situations.

As far as what blend mode to use that all depends on the passes your rendering and the look you want. There isn't an official correct way, but there are some pretty standard ones like light passes are usually put together additively. Shadow passes can be either normal, or multiply. It really all depends on what want for the look.

Tim J

jussing
08-31-2006, 09:56 AM
My basic technique is to multiply each light source pass with the unlit texture pass, and add or screen those together. Add reflections and specular on top of that.

Then you can tweak each layer's opacity, to optimize the result.

- Jonas

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08-31-2006, 09:56 AM
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