Following up on my previous question, but perhaps asking it more clearly:

1.  Is +SR/+ER supposed to give the same results as an extract from the full
image?

2.  Why doesn't it for my images?  (I get slightly different shadings in each
band.)  Could it be because of radiosity?  I've already turned off jitter
("-J"), though I don't know if I have to do that.

Thanks.

JH

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> Following up on my previous question, but perhaps asking it more clearly:
> 
> 1.  Is +SR/+ER supposed to give the same results as an extract from the full
> image?
> 
> 2.  Why doesn't it for my images?  (I get slightly different shadings in each
> band.)  Could it be because of radiosity?  I've already turned off jitter
> ("-J"), though I don't know if I have to do that.

I already replied. No, it's not supposed to give the same results if 
radiosity is involved.

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JH nous apporta ses lumieres en ce 2008/02/14 10:47:
> Following up on my previous question, but perhaps asking it more clearly:
> 
> 1.  Is +SR/+ER supposed to give the same results as an extract from the full
> image?
> 
> 2.  Why doesn't it for my images?  (I get slightly different shadings in each
> band.)  Could it be because of radiosity?  I've already turned off jitter
> ("-J"), though I don't know if I have to do that.
> 
> Thanks.
> 
> JH
> 
> 
> 
When using radiosity, the part of the scene that are not rendered are not 
treated the same as those that are actualy rendered.
You start by doing a render at a lower resolution and adding "save_file" in the 
radiosity block. Turn off antialiasing. You can also remove several transparent 
objects, like window panes. This will save the radiosity data to a file.
Those radiosity data are resolution independent.

You then do a second, full size or partial, render, with "load_file", 
pretrace_start 1 pretrace_end 1 and "always_sample off". Leave everything lese 
in the radiosity block the same.

There will still be some banding, but much less.

-- 
Alain
-------------------------------------------------
I believe that banking institutions are more dangerous to our liberties than
standing armies. Already they have raised up a monied aristocracy that has
set the government at defiance. The issuing power should be taken from the
banks and restored to the people to whom it properly belongs.
Thomas Jefferson

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Alain <ele### [at] netscapenet> wrote:

> When using radiosity, the part of the scene that are not rendered are not
> treated the same as those that are actualy rendered.
> You start by doing a render at a lower resolution and adding "save_file" in the
> radiosity block. Turn off antialiasing. You can also remove several transparent
> objects, like window panes. This will save the radiosity data to a file.
> Those radiosity data are resolution independent.
>
> You then do a second, full size or partial, render, with "load_file",
> pretrace_start 1 pretrace_end 1 and "always_sample off". Leave everything lese
> in the radiosity block the same.
>
> There will still be some banding, but much less.

Thank you for the detailed help.  I gave it a try, and I got a nicely
unbanded image, but I didn't get much radiosity detail.  Objects that
had vague shadows before now have no shadows.  I used 1/2 the
resoultion for the radiosity file.  (The final image was 640x480.  The
radiosity was 320x240.) Was this a mistake?

Rather than do this by trail and error (each render takes some 14
hours!), I'd be grateful for some guidance.

jh

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