On Sat, 20 Feb 1999 10:48:51 -0500, Matt Hilliard <hil### [at] erolscom>
wrote:

>For fun and practice I am working on a somewhat Generic 3D Space Battle
>sort of thing.  I'm sure its been done thousands of times before, but,
>well, the work->coolness ratio of 3D rendered spaceships is just
>irresistable, I guess.
>
>Anyway, I'm having some trouble with starfields and getting them to
>properly animate.  There are of course wonderful starfield textures
>which do not work in animations.  I'm sure you all know why and have
>answered this question a thousand times.
>
>And yes, I do have Chris Colefax's galaxy file.  However, using the
>object based starfield, I have been unable to get (a) a nice dense
>starfield and (b) figure out how to animate them.  By b I mean that when
>I rotate or translate it, instead of visibly moving the stars tend to
>fade in and out.  I'm sure I'm doing something wrong.
>
>So, what I'm asking here is if anyone can tell me the best way to do an
>animated starfield and, if there is no better way, perhaps a sample bit
>of code animating galaxy.sf (the animation example the include file
>comes with only animates a nebula).
>
>Sorry for asking what surely must be a FAQ, but I didn't see it in any
>of the FAQs I looked at.
>
Ken's got most of the answers here. Anti-Aliasing is probably your
biggest problem (don't I know it).

Exactly what movement you're trying to create will impact the
solutions but... my starfield animation (using C. Colefax's wonderful
starfield) is a simple rush-in-one-direction (for the main part) so I
cheated. A number of possible tips have evolved in my mind.

Look at the size of the stars - if they're realistically small (a
single point or close) at your chosen resolution then AA is likely to
cause you greif. Getting rid of AA or making the stars larger might
fix this. You might also like to carefully watch some of the "moving
starfeild" scenes on TV - I've paid attention to a few lately and keep
seeing the same "problems" show up time and again on TV... perhaps
fading is a natural result of seeing stars through different clouds
etc. etc. as the line-of-sight shifts slightly ?<g>

Look at the spread of stars - if you want most or all stars to appear
distant then the default may have too many near stars in it.

If you want to move through a starfield in a straight line then you
may find it difficult to get a sufficient density without running out
of the amount of RAM available on your continent. this isn't a problem
with the include file, it's a problem with the number of stars you
want to reproduce. Consider having not one sphere containing stars,
but a thread of star spheres along the path you want to travel. Care
must be taken to ensure you don't see thesespheres as seperate
entities anywhere in the animation.

Lastly, I'm no expert on POV or Mr. Colefax's include files - they've
just saved me a few years work is all. Try e-mailing him with some
specific queries - I've found him to be exceptionally helpful in the
past (and he's had nothing from me - not even an example of what his
work has done. I REALLY ought to do something about that).


Cheers,

Cliff Bowman
Why not pay my 3D Dr Who site a visit at
http://www.geocities.com/Area51/Dimension/7855/
PS change ".duffnet" to ".net" if replying via e-mail

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