Phil
08-21-2003, 05:51 AM
There seems to be a real problem with the multithreaded rendering in Layout - it doesn't produce the same results across the entire image.
Using 2 threads to utilise my dual processor machine here, there is a clear and reproducible flickering of the lens flare reflections in the fog that is arising from a different intensity of the drawn flares within the top and bottom parts of the image. If I render with a single thread, this problem is not seen. This is incredibly annoying.
The scene is too heavy on memory for the machine to render it as two separate LWSN instances, hence the attempt to use the multithreading approach. This issue just appears to affect the reflection elements of the lens flares, not the core flare itself.
What is more surprising is that these are supposed to be drawn after the rest of the image has been rendered out and so I am confused as to why there is no discernable difference between the output of each thread when lens flares are disabled. It sounds like a bug in all honesty and there appears to be little in the way of an effective workaround that I can come up with short of rendering everything on a single processor and having it take considerably longer.
On a separate note, are there technical reasons why the GI calculations are run on only one of the processors? Similarly geometry optimisation appears to be single threaded. I'm just curious, that's all.
Using 2 threads to utilise my dual processor machine here, there is a clear and reproducible flickering of the lens flare reflections in the fog that is arising from a different intensity of the drawn flares within the top and bottom parts of the image. If I render with a single thread, this problem is not seen. This is incredibly annoying.
The scene is too heavy on memory for the machine to render it as two separate LWSN instances, hence the attempt to use the multithreading approach. This issue just appears to affect the reflection elements of the lens flares, not the core flare itself.
What is more surprising is that these are supposed to be drawn after the rest of the image has been rendered out and so I am confused as to why there is no discernable difference between the output of each thread when lens flares are disabled. It sounds like a bug in all honesty and there appears to be little in the way of an effective workaround that I can come up with short of rendering everything on a single processor and having it take considerably longer.
On a separate note, are there technical reasons why the GI calculations are run on only one of the processors? Similarly geometry optimisation appears to be single threaded. I'm just curious, that's all.