View Full Version : from draft to production quality-huge increase in time

11 November 2006, 08:23 AM
This s my test of from draft to production quality
AA is: -1 2 and Filter box
I only change the sample of main area light and contrast threshold... Please look at the time to remove artifact
When changing from 10 to 25 sample, the time is huge but it s only play with the noise of light
Any suggestion to boost the time.. that will be a great help

11 November 2006, 10:49 PM
A contrast threshold of 0.02 is way too low! I've never used anything below 0.05 and you might not even need anything lower than 0.1 for this scene. You have your AA sampling set to -1, 2 right? You do that because you want simple areas of the scene to render really fast (-1 or 0) and then have it work harder on difficult areas (1 or 2). The way it figures out which areas are simple or difficult is by using your contrast threshold. Having the contrast threshold that low will make the whole scene be rendered using 2, meaning every pixel will be sampled 16 times. That's a lot of samples which is why it's so slow.

You should always turn up the area light samples first. In this case because your scene heavily relies on the quality of the area light sampling, it will look like you may need to turn up the AA samples, but really it's just because the low sampling of the area light adds artifacts to the whole image. Try setting your contrast threshold to like 0.1 or 0.07 but keeping the area light samples on 25 or maybe even increasing them to 32.


11 November 2006, 10:56 PM
According to the first post, he is using -1,2. But, it's a box filter. :sad:

Try repeating with a smoother filter e.g. Gaussian, Mitchell or even triangle. Again with threshold between 0.1 to 0.03. Lower your threshold before increasing the AA sample above -1, 2.

But, first check your area light. How big is it? Make sure it is no larger than it needs to be, otherwise much light sampling will be required.

11 November 2006, 06:55 AM
Thanks for all your advice... I will try them

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11 November 2006, 06:55 AM
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