Simon Wicker
11-05-2006, 08:37 PM
I don't think I have seen this mentioned before so I thought I would pass on a little tip for rendering an animation using stochastic mode GI in a more efficient way.
Basically you can speed things up by letting Cinema combine as much work as possible into the scene motion blur post effect.
Set your AA to none, turn your GI settings to stochastic and set your samples down really low, 8 or below, with a diffuse depth of 1 and then make sure you set identical noise distribution off.
Activate scene motion blur and set it to 16 or 25 samples.
Now when you render your scene the scene motion blur gives you really nice blur, the camera offset gives you decent AA and because you get a different distribution of noise in each pass for the GI when the frames are blended you get a smooth result from the GI so that your 8 samples are mixed multiple times and you get the equivalent of a much higher sample rate.
Best of all this is really quick as you are not using any oversampling to get decent AA and you are not having to up the stochsatic samples too much to get a smooth result from the GI.
Using this technique I have been getting around 15 minutes a frame for a flyover over of sixteenth century London that I'm working on currently (rendered at widescreen pal res of 1024x576). I should point out that this scene is all diffuse and does not contain any relective or refractive surfaces so I don't know how this technique would work in a modern architectural setting although it should still be better than using a brute force method of high stochastic samples for decent GI quality.
cheers, simon w.
Basically you can speed things up by letting Cinema combine as much work as possible into the scene motion blur post effect.
Set your AA to none, turn your GI settings to stochastic and set your samples down really low, 8 or below, with a diffuse depth of 1 and then make sure you set identical noise distribution off.
Activate scene motion blur and set it to 16 or 25 samples.
Now when you render your scene the scene motion blur gives you really nice blur, the camera offset gives you decent AA and because you get a different distribution of noise in each pass for the GI when the frames are blended you get a smooth result from the GI so that your 8 samples are mixed multiple times and you get the equivalent of a much higher sample rate.
Best of all this is really quick as you are not using any oversampling to get decent AA and you are not having to up the stochsatic samples too much to get a smooth result from the GI.
Using this technique I have been getting around 15 minutes a frame for a flyover over of sixteenth century London that I'm working on currently (rendered at widescreen pal res of 1024x576). I should point out that this scene is all diffuse and does not contain any relective or refractive surfaces so I don't know how this technique would work in a modern architectural setting although it should still be better than using a brute force method of high stochastic samples for decent GI quality.
cheers, simon w.