CGTalk - Shadows problem

cryo_7

12-01-2005, 06:06 AM

Hi,
I am rendering my scene using GI and FG. The scene is lit with sphere area lights with no intensity. The lights are emiting photons and they dont use either Depth map shadows or raytrace shadows. There are some bad shadows at some parts of the image, does anybody know how can I reduce that effect? My settings are:
GI Accuracy 400
GI Radius 30
FG rays 300
No falloff
trace Depth 20
trace reflection 10

Now I am rendering the same scene using FG-->Filter 2 instead of 0 (default)

Any suggestions? Do you like the lighting of the scene? Does it look realistic?

thank you..!

ghostlake114

12-01-2005, 06:17 AM

try to increase FG ray and reduce Max/Min radius (not 0 ) and you will have better image (but the time will increase :cry: :cry: )

cryo_7

12-01-2005, 06:28 AM

the above scene at 1600 x 800 took 13 hours to render...! Any other suggestions :) ? The diagonal length of the scene is 52 units. Should I try 0,52 in min and 5,2 in max?

thank you for the reply

ghostlake114

12-01-2005, 06:50 AM

Yes, theory is 5.2 and 0.52 Min and Max...
---
Normally, 300 FG is enough, but to eliminate all the weird thing in the pic, maybe we need to increase more :(
----
I know there are a script named smooth_FG at highend3d, but do not have time to test it... Can it be a solution???

cpan

12-01-2005, 07:13 AM

yes, try changing the FG max radius to higher values, even higher than 5.2.
btw what maya version do you use?

oh, and one thing... 13 hours?! what samples do you use for the area lights and how many lights do you have in scene? post some details about the scene settings (AA settings, global samples, etc), maybe a screenshot of the lighting setup.

cheers

LehaS

12-01-2005, 07:26 AM

Hmm...i noticed you mentioned sphere area lights...Why do use them if you don`t need area shadows?...
Do "area" properties of the light have any impact on photon emitting properties? Hmm...never heard of that..

Also do you use Maya default Area light or just default point light converted to MR area light?
In my expierience Maya default Area light proved to be buggy and unstable in some situations..
If i were you i`d consider using later i think...

Nice work btw ;)

cryo_7

12-01-2005, 11:16 AM

Changing FG-->Filter to 2 instead of 0 corrected the image. This 600 x 400 image took 3 hours to reder so it increased render time by 10% I ll try using min and max values at FG as ghostlake114 and yashu suggested. I ll also have a look at smooth_FG script at high end. [ I found a fantastic shader at highend called Plush 1.0 really usefull for velvet looking cloth ]

Leha, I am using point lights converted to MR area liights. Thank you all for your comments :)

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