Sunlight simulation

[Scrat]

Hi there I am trying to achieve a sunlight simulation. Here are the settings

FG on with Physical Sun and Sky
I rendered with a 100 frame step to produce the FG map (append to file)
it produced a FG map

I begun to render the scene

I used the use from file option and gave the path

Here is the result

<object width="425" height="355"><param name="movie" value="http://www.youtube.com/v/mkYHFbcGbcg&hl=en"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/mkYHFbcGbcg&hl=en" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object>

Can somebody explain me why I do not receive FG?

Thanks in advance!

[Scrat]

I rendered the scene with every frame's fg map recalculated... Time did not increase too much (from 50 sec/frame it went up to 1:30 sec /frame).. You can clearly see the difference... The thing I want to avoid is to recalculate for each frame the map.. Since the light changes I know that you have to calculate the map... Any suggestions?

Here is the new video

Video (http://62.103.249.244/users/ipiotis/simulation_with_fg.avi)

[Marco_VN]

The calculation of a FG-map stores the lightenergy (the reflected light) of the scene. It only makes sense for cameramoves in a static scene. If you move objects or change the light, the whole light-"energy" changes from frame to frame and has to be recalculated.

If you store the light in a FG-map by rendering every 100 frame, the map will be kumulative added with light shining from everywhere (like 10 suns lightning up your scene) and so you get these bad results.

Hope to clear it up,
cheers,
Marco