Raf256 <spa### [at] raf256invalid> wrote:

> 1) blurred reflection - I see it is suggested (in FAQ) to use several normal
> patterns (or textures) and strong antialias.
> How about using the old method - because I think it might benefit in speed,
> by using adaptive number of samples (same as in camera focal blur). The AA
> of entire image is not as good probably

The old method?

There was an alternative method mentioned on here, once, although you'll
have to search for it if you're bothered. The idea was to do multiple
renders of the scene in which you want blurred reflection. A normal (based
on whatever pattern) is applied to each reflective surface you want
blurred. For each render, translate the normal by a different amount (most
easily by using the frame_number as input to a seed(), I imagine). Then
average together all the images in your paint application or using a
script.

You may find this method more visually satisfying during rendering since you
can usually see some sort of progress; in my experience, the single-pass
averaged blurred normal method has the same effect on povray as I imagine
superglued running shoes do on a marathon runner. But more effort is
required outside povray, and there are probably accuracy issues, which may
or may not be a problem depending on application. I have only used this
method once (and gave up totally on the approved method at that time), and
I didn't demand much of the effect, so you should really experiment
yourself.

> 2) radiosity and light fading - natural light behaves like with fade_power 2
> right? What about the radiosity? It is calculate in such way that in
> example wall lighted directly by a light source will light other objects
> correctyl (acting a bit like light source with fade_power 2)?

I imagine so; as I understand it samples are taken evenly (although
randomly) on the surface of a hemisphere. As you move a neighbouring
surface further away from the one doing the sampling, it will naturally be
hit by fewer samples, in fact the number of hits will decline by the
square, just like fade_power 2. So the effect is built-in, I think.

> 3) It seem to be a problem to create a cololor that "only add" to backround.

Slime came up with a way to do this ("additive transparency", is I think
what you're after) and posted it on this very news server. It worked very
well for ordinary transparent materials (no need for media), IIRC. See:

http://news.povray.org/4202c5f8%40news.povray.org

and

http://news.povray.org/4202c6ad%241%40news.povray.org


Tom

Post a reply to this message