POV-Ray : Newsgroups : povray.binaries.images : Volume Control Final [~33kbu] : Re: Volume Control Final 2 [~79kbu] Server Time
16 Aug 2024 18:19:00 EDT (-0400)
  Re: Volume Control Final 2 [~79kbu]  
From: Hugo
Date: 12 Feb 2002 06:29:13
Message: <3c68fc89$1@news.povray.org>
> Still, it's not hyper-real, as I would have liked. I wish I could put my
> finger on what it lacks. I know something about the plastic just isn't
> right. I wish I knew what. <sigh>

I think I know what it is.. If you want to know.. It's 2 things:  The light
and the reflection.. Raytraced lights comes from an infinite small point,
and that's not realistic.. Look at the window next to you:  The light enters
the room from ALL the window; from the upper left corner to the lower right
corner, although there might be an angle where the light is most intense
(sunlight).

Even bulps are an "area" of light.. A small area, but since the light
usually bounces off the walls, it once again creates a very big area of
light.. You can simulate this in Pov with multiple light sources closely
around each other, either in shape of a window or a bulp, and use radiosity
for light bouncing off the walls.. Area_lights in Pov only makes the shadows
soft; they don't change the light itself.

Second thing is the reflection on the plastic. You use the specular keyword.
That's actually a shortcut for blurred reflection. The realistic thing would
be to turn off specular, and use blurred reflection. Even if there is just
the ground to reflect, this will be visible.

I know this smashes the render time, but there's no way around it..  :o/
You CAN however speed things up by using as few light_sources as possible
and by using Jaime Vives trick of a 2-pass rendering.. First save a
radiosity file rendered without blurred reflection. Then load the radiosity
file and render the scene WITH blurred reflection.. I would also mix the
specular keyword with a low-quality blurred reflection, for speed reasons.

Radiosity won't help the scene if there are no walls. Jaime's light macro
won't help if there are only small objects in the scene. I think it's mostly
useful with big scenes ala his office.

I hope this will help you.. Maybe you knew this already, but some people
probably does not..

Best wishes,
Hugo


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