Bryan Valencia wrote:

> I'm trying an outside scene on a cloudy day... it's the grass scene I have
> been posting.
> 
> But the sky_sphere is always beautifully lit, while the rest of the scene is
> essentially black.
> 
> Here are my settings, what's wrong?
> global_settings {
>  assumed_gamma .8
>  ambient_light rgb .3
> 
>     radiosity {
>       pretrace_start 0.08
>       pretrace_end   0.01
>       count 500
> 
>       nearest_count 10
>       error_bound 0.02
>       recursion_limit 1
> 
>       low_error_factor 0.2
>       gray_threshold 0.0
>       minimum_reuse 0.015
>       brightness 1
> 
>       adc_bailout 0.01/2
>     }

I'm going to go ahead and partly disagree with everyone here... ;D

First, the ambient_light global setting doesn't set a default ambient 
finish (that's what #default is for); it sets an ambient multiplier. So 
if you're using ambient finishes ANYWHERE in your scene, they will be 
multiplied by .3. If this is affecting your sky_sphere, that would be 
the cause of your problem.

Second, your count is way too high for an outdoor scene with a large 
open sky; you're wasting a lot of cycles on quality that you probably 
can't see. Try using 100 or less (30 would be plenty for test renders) 
and don't increase it unless artifacting is a problem with the settings 
you're using for the final render.

Likewise, your error_bound is way too low for most outdoor scenes; 
pretty much anything below .3 or so is only useful if you want really 
detailed radiosity shadows. Try a setting of .5 or so.

Your low_error_factor can probably be set to 1, especially if you decide 
to use a smaller error_bound. (Go look it up.)

Some people on these groups will recommend a ridiculously high 
recursion_limit. Don't listen to them, they're fools. Most outdoor 
scenes with wide open skies can get by with a recursion_limit of 1; 
indoor scenes will usually be fine with a recursion_limit of 2. The 
difference between 2 and 3 in most scenes is nearly invisible, and 
higher settings are useless for anything except *very* indirect 
lighting.. and even then, you'd probably want 16-bit output and 
post-processing to make any use of the data.

-Xplo

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