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View Full Version : Luminous polygons and shadows...



Cageman
04-22-2007, 10:21 AM
Hi there!

Now that LW9.2 has such a tremendous speedboost with radiosity, I wonder how you can render a shadowpass when using geometry and GI to lit a scene?

warrenwc
04-22-2007, 12:45 PM
Wouldn't you just use the shadow alpha?

Bog
04-22-2007, 01:19 PM
I would.

toby
04-22-2007, 03:55 PM
I don't think the shadow alpha works with radiosity, last time I tried it with Backdrop it didn't. As far as I can tell the shadow alpha only uses shadow buffers created by shadow maps or raytraced shadows. You'll have to render a pass with all white objects with GI to make your own alpha image.

Cageman
04-23-2007, 01:19 AM
I don't think the shadow alpha works with radiosity, last time I tried it with Backdrop it didn't. As far as I can tell the shadow alpha only uses shadow buffers created by shadow maps or raytraced shadows. You'll have to render a pass with all white objects with GI to make your own alpha image.

That was what I was thinking as well. Had to check if I would have missed a feature somewhere, but apparently not...

lets make some cutomized shadowpasses then... :)

Bog
04-23-2007, 04:15 AM
I don't think the shadow alpha works with radiosity, last time I tried it with Backdrop it didn't. As far as I can tell the shadow alpha only uses shadow buffers created by shadow maps or raytraced shadows. You'll have to render a pass with all white objects with GI to make your own alpha image.

You're kidding! That's... subnominal.

MooseDog
04-23-2007, 06:02 AM
I don't think the shadow alpha works with radiosity, last time I tried it with Backdrop it didn't. As far as I can tell the shadow alpha only uses shadow buffers created by shadow maps or raytraced shadows. You'll have to render a pass with all white objects with GI to make your own alpha image.

wouldn't that be an occlusion pass?

toby
04-23-2007, 10:21 AM
wouldn't that be an occlusion pass?
Not really, ambient occlusion doesn't consider luminous surfaces as light sources.

Intuition
04-23-2007, 11:25 AM
Not really, ambient occlusion doesn't consider luminous surfaces as light sources.

That should change. :thumbsup:

toby
04-24-2007, 02:48 AM
I think they're two different things, don't you? I do think that a radiosity buffer should be separable though.

MooseDog
04-24-2007, 06:21 AM
Not really, ambient occlusion doesn't consider luminous surfaces as light sources.

cool! nice distinction, thx for pointing that out:thumbsup:

hope you get a solution somehow, soon.