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Am 31.05.2010 14:06, schrieb Dave Blandston:
> I don't know if there's really anything wrong here, but just in case anyone else
> has experienced this situation I decided to show this example. Some darker
> rectangular areas appear when this scene is rendered with radiosity. It's a
> minor problem and probably something I'm doing wrong as usual, and I'm not
> asking for any help. During the modeling phase I tried to make sure there were
> no coincident surfaces, so I don't think that's the problem. (Version 3.7 Beta
> 37a)
I suppose it's typical artifacts from the radiosity code taking
additional samples during the final trace. Some pieces of advice to
prevent this effect:
- Use "always_sample off"
- Make sure your radiosity pretrace gathers a decent number of samples
already. From my experience, at least about half of all the samples
should be gathered during pretrace already. (If it doesn't, usually
decreasing pretrace_end will do the job.)
You can check this with the radiosity statistics. After render, POV-Ray
will output a table like this, listing the number of samples gathered
per pass and recursion depth:
--------------------------------------------------------
Pass Depth 0 Depth 1 Depth 2 Total
--------------------------------------------------------
1 1544 40899 7794 50237
2 6079 72001 2232 80312
3 22457 95237 1677 119371
4 66516 106702 1274 174492
5+ 246562 139354 2603 388519
Final 46489 161 - 46650
--------------------------------------------------------
Total 389647 454354 15580 859581
Weight 0.199 0.057 0.027
--------------------------------------------------------
In the "Depth 0" column, the "Final" value should be no more than about
half of the "Total" value.
(The example shows a render that took more than 88% of all samples
during a 6-pass pretrace, so that can pretty likely be cut down to 5
passes by doubling pretrace_end to increase speed.)
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