POV-Ray : Newsgroups : povray.general : Max world size? : Re: Max world size? Server Time
5 Jul 2022 06:18:59 EDT (-0400)
  Re: Max world size?  
From: Bald Eagle
Date: 4 Jun 2022 07:25:00
Message: <web.629b3ff7e9a0fbb21f9dae3025979125@news.povray.org>
"HackerDaGreat57" <Hac### [at] gmailcom> wrote:
> I'm pretty new to POV-Ray and have gotten somewhat experienced with its
> coordinate system and how it places cameras.
> I'm wondering what is the limit for coordinates? Take Blender, for example - it
> starts losing precision after a few thousand meters, but what about POV-Ray?
> TL;DR: What is the max reliable coordinate number in POV-Ray

Well, I've never actually pushed that envelope that far, and in that manner.

But I would imagine that if we're using a source code version based on 32-bit,
then it would be inherently limited by:

The range of a 32-bit integer is from -2.14 billion to +2.14 billion, which is a
range of 4.28 billion, which is 232nd.

I usually try to limit my numbers to 1 x 10 ^ (+/-) 6 if at all possible.


I'm sure Bill Pokorny and others have delved into the gory details of this and
have a much more accurate sense of min/max.  I think that usually people run
into the most problems with the small numbers, because there are several
different places in the code, which may use different cutoff values.

If your values are too large, then your objects may simply disappear.

If you're doing a static scene, you may just want to use a scaling factor that
brings everything into a nice, manageable range of values.

If you're doing an animation, you might want to think about constructing your
scene such that your camera is at or close to the origin, and everything else is
defined in relation to that.  You may also want to consider implementing some
form of proximity and Level-Of-Detail scheme to detrmine if things are close
enough to the camera to even bother instantiating, and how the geometry and
texturing should be implemented.   There's no reason to use an image-map on an
isosurface object that's so far away that it will only be seen as a
color-averaged, antialiased 4 pixel blob....  render it as a simple pigmented
sphere instead.

- Bill

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