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Ernest Burden
11-30-2005, 06:25 PM
I posted this on the FR2 forum, but since its not all that active, and I need to figure this out soon to complete a project, well, I should ask here too:

I have a light gel. Its a poly with a color gradient mapped onto it. In C4D I set a composite tag with just 'cast shadows' and 'seen by transparency' checked, and the material has the gradient in the transparency channel. No other channels on. This sits in front of a light and the colors are cast by the light.

How to make this work with fR2? I have an object tag with just 'cast shadows' and 'seen by refraction' with the same material, but it just makes a solid black shadow. I've tried putting the gradient in the luminence channel, no go, still black shadow.

How to do this rather simple task and have it render the same in fR2 as AR?

JamesMK
11-30-2005, 07:06 PM
If the gradient is placed in the transparency channel, then it renders as expected in FR too as long as you set the light to use hard shadows. Soft shadows don't work for this purpose (and as far as I know, C4D is pretty unique in that it actually picks up colours from transparencies with soft shadows)




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Ernest Burden
11-30-2005, 07:46 PM
If the gradient is placed in the transparency channel, then it renders as expected in FR too as long as you set the light to use hard shadows.

The light is my 'sun'. It is set to raytraced/hard shadows.


In testing, I'm finding more oddness with alphas, too.

lllab
12-01-2005, 07:05 PM
"and as far as I know, C4D is pretty unique in that it actually picks up colours from transparencies with soft shadows"

..not true, most highend and even most midend renderengines do that today. what you say was years ago!

do a search;-)

cheers
stefan

JamesMK
12-01-2005, 07:07 PM
Whatever, the point was that FR only makes a coloured shadow with hard shadows, but not soft shadows.




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lllab
12-01-2005, 07:21 PM
does it with area shadows i hope!!???

cheers
stefan

JamesMK
12-01-2005, 07:22 PM
does it with area shadows i hope!!???
Yes it does

Ernest Burden
12-01-2005, 08:43 PM
Shadowing via transparency is quite old. I did that with Lightscape many years ago.


To follow up on this--in a discussion in the FR2 forum ir was determined that there was a problem with the exact geometry I was using. We still don't know what or why, but the ability to cast colors via transparency is alive and well in FR2/C4D.

Here's what I do with it:

http://www.oreally.com/temp/FR2-GI-01.jpg

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