|
 |
POVMAN wrote:
> Can anyone tell me in laymans terms what the "pretrace" settings in
> radiosity does?
The pretrace makes the renderer run across the image area in a coarse
(and successively finer) pattern and trace the pixels with modified
radiosity settings (the modifications being low_error_factor and
always_sample) before doing the actual render.
The pretrace settings adjust what grid stepping is used for the pretrace.
> My recent renderings have not shown any significant
> differences when changing this value.
The pretrace influences the distribution of radiosity samples. There
are a lot of cases where this does not make much visible difference but
in general the results *always* differ when changing the pretrace
settings (the difference might be too small to see).
Christoph
--
POV-Ray tutorials, include files, Landscape of the week:
http://www.imagico.de/ (Last updated 27 May. 2006)
MegaPOV with mechanics simulation: http://megapov.inetart.net/
Post a reply to this message
|
|
|
|
POVMAN nous apporta ses lumieres en ce 30/05/2006 05:12:
> Can anyone tell me in laymans terms what the "pretrace" settings in
> radiosity does? My recent renderings have not shown any significant
> differences when changing this value.
>
Using smaller pretrace_end values can allows you to use lesser radiosity settings
while preserving
the quality. In some cases, this can improve the rendering time. Shifting
pretrace_start a little
bit up or down can, in some cases, reduce or remove some artefacts.
As each pretrace step use half the tile size as the preceding, it's probably best to
use a
pretrace_end valus that is = to pretrace_start / (2^x) "x" been 1 less than the total
number of steps.
--
Alain
-------------------------------------------------
Post a reply to this message
|
|
