You can't load and save a radiosity map at the same time.

When I first read this, it seemed fairly obviously. But now, several 
years later, it ocurrs to me - you might actually want to do this. For 
example, if I wanted to render an animation with radiosity [oi! stop 
laughing at the back there!] it might be nice if each frame could use 
the rad data from previous frames, and also if it needs to take any 
extra samples itself, add them back to the file...

Is there a technical reason why you can load and save at the same time? 
Or is it just that nobody thought it would be a useful thing to do? (I 
don't expect this will be changed *any* time soon - everybody is still 
trying to get the new beta working right now...)

I suppose if I was feeling really psychotic, I could write a program to 
take several radiosity files and merge them together... then I could 
render the scene from all the angles that will be used, and merge the 
resulting files. Not quite as good, but it's something.

[And of course, all of this assumes the scene isn't going to *change* 
during the animation - that would totally alter the rad data!]

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"Orchid XP v2" <voi### [at] devnull> wrote in message 
news:43513330$1@news.povray.org...
> You can't load and save a radiosity map at the same time.
>
> When I first read this, it seemed fairly obviously. But now, several years 
> later, it ocurrs to me - you might actually want to do this. For example, 
> if I wanted to render an animation with radiosity [oi! stop laughing at 
> the back there!] it might be nice if each frame could use the rad data 
> from previous frames, and also if it needs to take any extra samples 
> itself, add them back to the file...
>
> Is there a technical reason why you can load and save at the same time? Or 
> is it just that nobody thought it would be a useful thing to do? (I don't 
> expect this will be changed *any* time soon - everybody is still trying to 
> get the new beta working right now...)
>
> I suppose if I was feeling really psychotic, I could write a program to 
> take several radiosity files and merge them together... then I could 
> render the scene from all the angles that will be used, and merge the 
> resulting files. Not quite as good, but it's something.
>
> [And of course, all of this assumes the scene isn't going to *change* 
> during the animation - that would totally alter the rad data!]

Hi Andy,

It's been a year since I attempted this, but I am quite sure it IS possible, 
or I must have been hallucinating.  I used it for a camera animation 
sequence, where radiosity calcs were added to the file in each frame.

But at first, I couldn't get it to do this.  Then I discovered where I was 
going wrong:  DON'T use .RCA extension for save_file_name and 
load_file_name!  It gets nixed to zero by the opening of the temporary 
working file for write!

Instead, change the save_file_name and load_file_name to, eg "filename.rad", 
and it's alright.

It'll:
1. Load data from opening the filename.RAD file for read,
2. Write new samples to the temporary working filename.RCA file,
3. When done, rewrite the lot to filename.RAD and delete filename.RCA

HTH
Brian

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"Brian Elliott" <NotForSpam@AskIfUWant> wrote in message 
news:4352507c$1@news.povray.org...
> It's been a year since I attempted this, but I am quite sure it IS 
> possible, or I must have been hallucinating.  I used it for a camera 
> animation sequence, where radiosity calcs were added to the file in each 
> frame.

PS,  I HAVEN'T tried this with the 3.7 beta.  Err, what else..  Yup, also 
beware that after some time into the animation, the sheer mass of 
accumulated radiosity data could get so large that it takes LONGER per frame 
to load the data and render the frame, absorbing huge slabs of RAM in the 
process, than it would have been emptying it and continuing with a clean 

around a static object, so the file eventually stored data for a lot of 
off-screen geometry and was more than 200MB in size.

Cheers again,
  Brian

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