LC #42 Pipers Alley

View Full Version : Help Rendering Advanced Passes!

01-24-2007, 12:25 PM
Hi, I need to know how to render a FinalGather pass without the "AO"-looking shadows.
And how to render a seperate keylight pass.
This is because I want to use a "clean-color" (named HDR Convolve in the image) FG pass and a separate AO pass and a KeyLight pass in comp to get more control.
I'm using Maya 8 and MentalRay.

Here is a example image of what I meen, these images are rendered in Renderman (not by me).

I'll be really thankful for your help.

01-24-2007, 03:19 PM
( s what I am asking 4
Your pass is AO pass
KeyLight pass is shadow pass
HDR convolve is somekind of indirect pass + diffuse pass
so sad, they shadow pass, as mentioned in thread above, could not be extract unless we use p_shader of puppet

01-24-2007, 06:10 PM
ghostlake114 (, have you created a HDR (convolve) pass youreself, in maya and mentalray, plese tell me how?

01-25-2007, 01:49 AM
AFAIK, there is no way to generate that pass seperated from the shadow pass, unless we use p_shader pack. The other way is just a trick. turn off recieve shadow and cast shadow when render and you got that pass

01-25-2007, 07:05 AM
For rendering "HDR convolve" pass you just need "p_environment" or "Dirtmap" shader (and maybe some other occlusion shaders).
p_environment - just assign and render and you'll get same result.
Dirtmap - enable 'Trace Environment' and disable 'Trace Probe'.

01-25-2007, 01:27 PM
can someoen please explain what exactly is an hdr convolve pass ?
thank you

01-25-2007, 09:04 PM
can someoen please explain what exactly is an hdr convolve pass ?
thank you

I think in this case the convolve pass is basically ambient light generated from the HDR image. You can use the ambient occlusion pass to subtract the places where the ambient light doesn't reach.

01-25-2007, 10:18 PM
so, if i got this right it's basically a cheap way (in terms of performance) to fake
an FG pass?

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