Hi everyone,

I want to achieve the following, I want to render a GI solution with final
gathering for a scene, but what I want to do to improve the FG solution is
to:

I want to move the camera on a circle at a certain height around and gather
the FG for each camera position.

How do I achieve this best?

Regards,

Thor

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McHannemann nous apporta ses lumieres en ce 13-02-2007 14:25:
> Hi everyone,

> I want to achieve the following, I want to render a GI solution with final
> gathering for a scene, but what I want to do to improve the FG solution is
> to:

> I want to move the camera on a circle at a certain height around and gather
> the FG for each camera position.

> How do I achieve this best?

> Regards,

> Thor

Have NO idea what you mean by "GI solution" nor "FG solution", but...

For the camera part:
In an animation, rotate the camera acording to the clock variable around the y 
axis (+y is UP in POV-Ray).
camera{Camera_Deffinition rotate y*clock*360}

If you want to gather radiosity data for the whole thing, save the radiosity 
data on each frame using a custom name and reload that starting on frame 2. The 
data from each frame will get added to that from the previous ones.

-- 
Alain
-------------------------------------------------
'No, `Eureka' is Greek for `This bath is too hot.'' -- Dr. Who

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> I want to achieve the following, I want to render a GI solution with final
> gathering for a scene, but what I want to do to improve the FG solution is
> to:

In general, for a single fixed image in POV-ray it isn't necessary to
separately gather radiosity information. Some good radiosity settings
are ...

radiosity {
   brightness 3
   count 100
   error_bound 0.15
   gray_threshold 0.0
   low_error_factor 0.2
   minimum_reuse 0.015
   nearest_count 10
   recursion_limit 5
   adc_bailout 0.01
   max_sample 0.5
   media on
   normal off
   always_sample 1
   pretrace_start 0.08
   pretrace_end 0.01
}

> I want to move the camera on a circle at a certain height around and 
> gather
> the FG for each camera position.
> How do I achieve this best?

The improvement in such a setup is extremely small, but it's possible to
use a multi-frame animation and save_file and load_file to develop better
radiosity data. Then just save in the first frame, load and save in the
remaining pre-radiosity frames, and use always_sample_off in any
final output frames to keep the radiosity data from changing between
frames. The data is collected from the camera's location, move the camera
around in a circle.

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> Have NO idea what you mean by "GI solution" nor "FG solution", but...
I had to think about for a while too...
GI = global illumination
FG = final gather (a Maya term for gathering radiosity samples)

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As I understand it, many renderers use photon maps to get a rough global
illumination "solution". If used alone to determine indirect illumination,
the result can be very blotchy and artefacted as the photon maps are
usually quite coarse, but final gathering is a way to clean them up. There
seems to be a good visual demonstration (not explanation) here:

http://homepages.paradise.net.nz/nickamy/finalgathering.html

I doubt the rendertimes given there are representative of a production
renderer.

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