I was comparing default radiosity values as well as comparing precomputation of irradiance.
In the image below, there are four renders of two identical, joined rooms, with a light hovering in the middle of the adjacent room.
The first column represents the default values for radiosity. Those values are:
Photon Cast: 10,000
Sample Area: 100
Photon Samples: 100
Intensity: 100%
Max Bounce: 15
Caustics: OFF
Samples: 100
Jittering: 0%
The second column represents the suggested values for radiosity. Those values are:
Photon Cast: 100,000
Sample Area: 1100 (This value was calculated using PhotonSetup Provided by Yves)
Photon Samples: 100
Intensity: 100%
Max Bounce: 15
Caustics: OFF
Samples: 200
Jittering: 20%
The first row has precomputation of irradiance turned ON, while the second row has precomputation of irradiance turned OFF. With the precomputation of irradiance off, the quality of the image is enhanced and many visual artifacts are eliminated.
Render Times:
Radiosity Default Values
Time: 0:02:35
Radiosity Default Values No Precomputation of Irradiance
Time: 0:02:36
By turning precomputation of irradiance off, rendering this image took 0.01% longer.
Radiosity Suggested Values
Time: 0:06:01
Radiosity Suggested Values No Precomputation of Irradiance
Time: 0:09:03
By turning precomputation of irradiance off, rendering this image took 33.52% longer.
All images are Gamma Corrected by 2.2.
Full Version: Precomputation of Irradiance
Hash, Inc. Forums > Technical Direction and Development (Learning Animation:Master) > A:M Rendering, Compositing and Special Effects > Texturing, Lighting and Effects > Lighting Effects
when u dont compute irradience, it looks kinda crappy....
(light comin through the walls)
Ben
(light comin through the walls)
Ben
The light coming through the walls happend when I turned precompute irradiance to ON. It went away when I turned it off. The image below shows precompute irradiance set ON and OFF.
Both pictures have visual artifacts, but the one that was rendered without the precomputation of irradiance looked much better.
The other two images shows the problems with both of the renders.
Both pictures have visual artifacts, but the one that was rendered without the precomputation of irradiance looked much better.
The other two images shows the problems with both of the renders.
Precompute Irradiance is faster but slightly less precise.
The difference in render time will become more noticeable with larger renders. The irradiance pre-computation step will not take more time as image are larger. But the on-the-fly computation will take proportionally more time as rendered image gets larger.
As is usually the case with rendering techniques, you have to choose the best tradeoff between speed and quality.
The difference in render time will become more noticeable with larger renders. The irradiance pre-computation step will not take more time as image are larger. But the on-the-fly computation will take proportionally more time as rendered image gets larger.
As is usually the case with rendering techniques, you have to choose the best tradeoff between speed and quality.
Tradeoffs are tuff, but I say "quality over quantity", or in this case; speed. 
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