POV-Ray : Newsgroups : povray.general : Novice question Server Time
11 Aug 2024 15:16:53 EDT (-0400)
  Novice question (Message 1 to 2 of 2)  
From: cadman
Subject: Novice question
Date: 4 Jul 1999 18:52:00
Message: <377fe590@news.povray.org>
I'm sure this is a stupid question:  How do I diminish the intesity of a
light?

Related(?):  Can someone explain in English how fade_distance works?  For
example, in a room, where there is a dim lamp on the desk that's supposed to
only illuminate the 60" (or units) surrounding it.  What would the
light_source object code be?

Thanks much.


Post a reply to this message

From: Mike
Subject: Re: Novice question
Date: 4 Jul 1999 23:37:44
Message: <378026CE.7B405A89@aol.com>
Fade_distance is the solution.  I honestly don't do the math when I use it.  You
can't really make the light fade to black, since it's an exponential falloff
(fade_power is your exponent I think).  As the documentation explains, the
fade_distance is the distance at which the full intesity of the light arrives.
After that it diminishes in intensity.

Basically this is how I do it:

1)figure out how far the object is I want it to hit

2)Add that to fade_distance but overshoot it a little.  For example if I was
going for 60, I would maybe make fade_distance 80.

3)Include a fade_power.  I like 2 as it seems to be somewhat realistic, though
I'll use something closer to 1 if things are looking too dark.

If you really want to limit the distance of a light, use fade_power 3.  This is
good for when you have a large number of lights close to together.

In terms of your example, I might try fade_distance 30 and fade_power 2.  That
should create a nice falloff to the light at the radius you describe.

-Mike

cadman wrote:

> I'm sure this is a stupid question:  How do I diminish the intesity of a
> light?
>
> Related(?):  Can someone explain in English how fade_distance works?  For
> example, in a room, where there is a dim lamp on the desk that's supposed to
> only illuminate the 60" (or units) surrounding it.  What would the
> light_source object code be?
>
> Thanks much.


Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.