View Full Version : Global illumination

07-23-2008, 11:12 PM
Have a look at the attached scene, can someone tell me why there is such a contrast between the lit area and where it starts to go dark?... You would expect there to be a smoother transition no ?

07-24-2008, 12:11 AM

Well below is an image showing a quick test I did with your scene. The only change made was rotating the camera to look down the tube at the bright end of the hall and pulling it back a bit so we are behind the sphere.

I'm not sure what you are seeing on your screen, depending on your screen settings (gamma, brightness, contrast, etc) we may see very different things even with the same settings.

The image below shows the settings I used for Final Gathering (FG) and Global Illumination (GI, aka photons). Using both gave, in my opinion, a better look. However even with lowering the photons from 2 million to 20 thousand the GI + FG render took more time, so be warned. I just wanted to show that if you do choose to go with GI + FG you can use alot less photons and FG accuracy then if you used either one singularly.

If you want to adjust the brightness and contrast of your images while you are in XSI, look into adding a simple tone mapping shader to your camera lense.


Let me know what you think.

~ JamesCG

07-24-2008, 07:19 AM
I think that the picture is inaccurate based on the fact that we have a smooth tube!
There is a stark contrast between white and black where the tube bends where i would expect there to be a nice smooth gradient...

I dont know maybe i'm wrong... maybe this is indeed how it would look in real life ! :-S

07-24-2008, 07:55 AM
i'm doing an animation of the camera moving down the tube and going round the bend ill post the results.

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07-24-2008, 07:55 AM
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