[Radiance-general] Ambient file Q's

[Rob Guglielmetti]

Fitzsimmons, Rob wrote:

> I rendered a series of images with -ad 2048 -as 1024 -ar 52 -af  
> file.amb (taking many hours to render)
> They came out splotchy, so I increased -ad 4096 -as 2048 -ar  200 -af 
> file.amb (building upon the same data)
>  I expected it to take quite a while to render, but they took ~ 5 to 10 
> minutes and I saw no real improvement
> my question is the nature of the ambient file..
> If I start it with a lower quality, can I improve it? Or is it similar 
> to trying to "upres" a Photoshop from 300 dpi to 600dpi

Hi Rob,

I'm assuming you used rpict directly, and not rad?  Anytime you change 
the rendering parameters you have to delete the ambient cache.  Rad does 
this for you automatically.  My guess is that you didn't do that, so 
there's the reason for both the speedy rendering and the negligible 
difference in image quality avan after doubling your ambient parameters.

So no, as I understand it, an ambient file seeded under lower quality 
settings will not improve when you re-run with higher settings.  You 
must start over.

As for the splotchies, maybe some more detail about your model would 
help us troubleshoot that, or maybe a sample image?

----

      Rob Guglielmetti

e. rpg@rumblestrip.org
w. www.rumblestrip.org