CGTalk - light fog issue

Ohlda

11-05-2006, 01:26 PM

Hi you lighting experts out there!

I am working on a CG shot for a short movie; i have to make a coin which is falling into a box, viewed from the inside of the box;

I am using light fog / physical light and I am getting some artefacts in the area where the coin blocks the light (see first pic);

I tried to adjust global illumination accuracy, radius, number of emitted photons and caustics; caustics radius, accuracy, but nothing gets me out of that problem...

The moment the coin is out of the way of the light, the artefacts disappear (see second pic)

I would be very happy if someone of you could give me advice how to solve this problem

Regards,

m°

pic 1:
http://www.rauschundluxus.roger-provide.net/CGpics/5Cent_10_06_c.jpg

pic 2:
http://www.rauschundluxus.roger-provide.net/CGpics/5Cent_10_07_c.jpg

gringer

11-07-2006, 06:29 AM

Hey,

There's 2 things I can think of.

1. If you used displacement on the coin to get it's details or acutally modeled them on, they could be causing the grain. What I mean is, when the volume light hits the coins surface and casts shadows around it, the geometry on the coins surface could also be casting many smaller more detailed shadows. Thus the weird artifacts where small beams of the white light are casting out.

2. You could try (if you havn't already) enabling global supersampling to smooth things out.

I hope that helps,

Cheers :D

henrymop

11-09-2006, 08:10 PM

Might try turning down the bias on the any lamps with shadows.

Ohlda

11-24-2006, 12:24 PM

Didn´t find time to try out your suggestions - as soon as I check it I let you know

- thanks for now!

m°

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