CGTalk - Radiosity Without Any Light/lum??

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Peoples

03-02-2003, 02:21 PM

I noticed a strange thing. I rendered one of my carmodels with a scene that contains a floor and a sky - both the same material, no luminosity activated. I have no lights in the scene. The car is visible only because it reflects the color of the sky. But when I render it w/out radiosity- it gets pretty dark. If I activate radiosity - the scene becomes much brigter and I also get a shadow under the car!!?? How come!! I thought radiosity need a ligth or a luminoius material to work -but I have neither but still I get a prepass with lots of dots and a bright scene??

Srek

03-02-2003, 02:24 PM

Hi,
are you sure you have deactivated the Auto Light?
Regards
Srek

Peoples

03-02-2003, 02:28 PM

yep - this is really strange..... - I thought that I´d get identical renders if I have nothing that radiates in the scene......Hhmmm:rolleyes:

Srek

03-02-2003, 02:37 PM

In this case i would strip the scene one object after the other and see when it gets dark. Or simply delete one texture after the other.
Regards
Srek

AdamT

03-02-2003, 03:16 PM

If you're relying on the "Seen by GI" option in the compositing tag you should be aware that it has no effect in R8--at least it doesn't on my install.

Peoples

03-02-2003, 03:27 PM

I'm using R7 and I have nothing in my scene besides my car, a plane and a sky object. None of my materials have luminosity chanel and I have no lights and unchecked the autolight... This is not a problem - the render is actually pretty nice, I'll post it once it finishes, but I'm just trying to figure this out - it seems pretty strange....

ThirdEye

03-02-2003, 03:38 PM

GI doesn't need luminous materials at all, colour is enough.

LucentDreams

03-02-2003, 04:57 PM

Originally posted by ThirdEye_01
GI doesn't need luminous materials at all, colour is enough.

Exactly, check you illumination settings in the sky material, even though your using olour instead of luminaces the sky is still illuminating the scene, just with less intensity. in the illumination settings there is a generate setting, reduce that to 0 and oyu should have the same results.

Peoples

03-02-2003, 05:54 PM

well - I would have been supprised if Thirdeye and Kai didn't know the answer to this one..:thumbsup:

Thanks guys - one thing less to learn about cinema...

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