[Radiance-general] estimating -av values, color

[Rob Guglielmetti]

On Mon, July 25, 2005 2:06 pm, Carsten Bauer said:

> Hi Rob,
> implementing this is more or less rather easy, I remember having played
> around with it some years ago already, but I didn't find it rewarding
> resp. worth the effort. The basic problem is always the 'flat'
> illumination caused by the constant value.

Agreed, but the direct calculation still puts some variation on those
objects that have the constant -av approximation, and if you could have a
variety of -av approximations to apply, one could have a fair amount of
variation in the scene, even with the excludes.  It could help, anyway.

> When it comes to image generation, if you have large scenes with
> exterior and interior parts both of importance for display in the image,
> and/or e.g complex stuff like trees etc, you should give the 'scene'
> feature of radzilla a try, with it's possibility of setting a separate
> parameter set meaning also separate caches.

I really, really should.  I recall reading about that and thinking that
that was a very good option for these kinds of scenes.  (I also think that
your falsecolor material is just too cool.)

> It depends of course on the type of object. Computers are fast now, so
> even in million polygon octrees like a tree e.g a crude ambient cache
> with -ab1 and -ad 60 or 100 or so is trackable. In such an obect the
> errors caused by the crude cache are of no importance,  and  it
> definitely gives better results than any constant value  approximation.
> In other cases, if the outside part is of lesser importance but still
> somehow visible in the image, setting -ab 0 and a constant av for the
> whole outside part might of course suffice, and it can save you the time
> and work of pasting some background stuff into the image with photoshop
> etc later..

Photoshop has no place in my Radiance workflow. =8-)

-- 
Rob Guglielmetti
www.rumblestrip.org