Multipass rendering - shadow layer

[SP00]

I was wondering what is the best way to handle a shadow layer pass. I've used the PSD export approach and rendered out a "final render" set and "shadow" pass with that. Then I moved shadow over the diffuse layer and blend it using color burn. This worked great, but edges around the ball object has problems, as you can see some white edge bleeding. I've attached an example below.

Now, I notice that the color burn blend only works with shadow maps and does not work with ray traced shadows. My third attach image shows that ray traced shadows causes some problems and gives the shadow a difference color instead of removing them.

So basically, I'm having problems and was wondering if there is a better solution. I can always paint out the white edge bleeding, but I rather use a different solution, especially if I decide to use animation.

Any help will be much appreciated. Thanks.

[SP00]

sorry, I meant to say color dodge instead of color burn. Thanks.

[dwburman]

I've seen tutorials where people said not to use the shadow pass directly, but to use it as a matte for another tool that darkens the image.

In shake I'd run the shadow pass into the matte dohicky on gamma or brightness node. In Photoshop and After Effects you can use it to control the opacity of an adjustment layer.

[Andyjaggy]

matte dohicky

That's the incorrect term, the correct term is matte knobby thungamajigger connector.

[kopperdrake]

Don't you just hate people who actually read the manual ;)

[Captain Obvious]

I typically use the shadow pass as the matte for an HSV lookup in Shake.

Preferably, I also split up the main render so I have the illumination separate from the textures. That makes it a LOT easier.

[SP00]

Thanks guys, but maybe I"m not asking the right questions, I guess what I am asking is what would be the best way to get a "diffuse lighting" pass and shadow pass separated for greater control? PSD export does not give me a "diffuse lighting" pass without shadows, which limits how I can control the shadows in post. I try to negate the shadows in the "diffuse lighting" pass but it gives me white edges, which doesn't make things better. So I would have to create the diffuse pass and shadow pass in a difficult manner, but not sure what that method is. Any help would be great in creating a "diffuse lighting" pass without shadows.

Here is the PSD files if you guys want to check out what I mean. Thanks.

[Andyjaggy]

That is one of the issues with Lightwave passes. The diffuse and shadow are combined, I don't believe there is any way to change this.

[SP00]

Darn it, maybe they can address this rendering issue soon.

[Andyjaggy]

Don't count on it. People have been asking for this to be fixed for a long time now. But eventually, yes, I think it will get fixed.

[SP00]

I sent a feature request, hopefully it helps push things forward.