Ah, I knew that... :)

Grim

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Josh English <eng### [at] spiritonecom> wrote:
: If you have a bunch of spheres, then collision detection is easy, but
: costly in parsing time.

  You mean easy relatively speaking?-)

  Yes, it's easy in the sense that you can easily write the appropriate code
with pov-script (even with pov3.1).

  But the math is not so easy. You need to know some physics math (momentum
calculations and so on) to get the collisions, resulting speeds and directions,
etc accurately.
  For example, it's not easy at all to make the math to simulate a pool
game (and this is in 2D).

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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On 5 Sep 2000 10:19:23 -0400, Warp <war### [at] tagpovrayorg> wrote:

>  For example, it's not easy at all to make the math to simulate a pool
>game (and this is in 2D).

It's quite easy to do the basics. Once you get into english (it
shouldn't be capitalized here, right?) and spin and masse and jumps...
then it gets tricky. I should know, I tried and gave up.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] usanet
TAG      e-mail : pet### [at] tagpovrayorg

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To my knowledge, this is the only case where "English" is not capitalized.

Surprisingly, I can't find any websites about the subject. I found a
glossary of pool terms, but all the terms were in all caps. Go figure.

Josh

Peter Popov wrote:

> On 5 Sep 2000 10:19:23 -0400, Warp <war### [at] tagpovrayorg> wrote:
>
> >  For example, it's not easy at all to make the math to simulate a pool
> >game (and this is in 2D).
>
> It's quite easy to do the basics. Once you get into english (it
> shouldn't be capitalized here, right?) and spin and masse and jumps...
> then it gets tricky. I should know, I tried and gave up.
>
> Peter Popov ICQ : 15002700
> Personal e-mail : pet### [at] usanet
> TAG      e-mail : pet### [at] tagpovrayorg

--
Josh English -- Lexiphanic Lethomaniac
eng### [at] spiritonecom
The POV-Ray Cyclopedia http://www.spiritone.com/~english/cyclopedia/

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My dictionary says that the pool term is "often" spelled without caps, which
would lead me to believe that either is acceptable.

Kevin Jackson-Mead
http://www.mindspring.com/~jacksonmead

Josh English wrote:

> To my knowledge, this is the only case where "English" is not capitalized.
>
> Surprisingly, I can't find any websites about the subject. I found a
> glossary of pool terms, but all the terms were in all caps. Go figure.
>
> Josh
>
> Peter Popov wrote:
>
> > On 5 Sep 2000 10:19:23 -0400, Warp <war### [at] tagpovrayorg> wrote:
> >
> > >  For example, it's not easy at all to make the math to simulate a pool
> > >game (and this is in 2D).
> >
> > It's quite easy to do the basics. Once you get into english (it
> > shouldn't be capitalized here, right?) and spin and masse and jumps...
> > then it gets tricky. I should know, I tried and gave up.
> >
> > Peter Popov ICQ : 15002700
> > Personal e-mail : pet### [at] usanet
> > TAG      e-mail : pet### [at] tagpovrayorg
>
> --
> Josh English -- Lexiphanic Lethomaniac
> eng### [at] spiritonecom
> The POV-Ray Cyclopedia http://www.spiritone.com/~english/cyclopedia/

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"Warp" <war### [at] tagpovrayorg> wrote in message
news:39b500eb@news.povray.org...
>   But the math is not so easy. You need to know some physics math
(momentum
> calculations and so on) to get the collisions, resulting speeds and
directions,
> etc accurately.

Not if you just blow up everything that hits something! :)

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GrimDude wrote:
> 
> Has anyone done anything like this?

	If you remember that collision detection is an exhaustive test, yes,
lots of people have done it. Collision detection in game machines are
dedicated sprites and colligion registers or are background parallel
routines in machines without collision registers. 

	If you are going to drop random sized and shaped things into your POV
file rotsa ruck on finding a fast was to avoid collisions. 

	There are plenty of strategies for it depending upon what you have in
mind. 

-- 
The US fought Germany in WWII because Germany
declared war on the US.
	-- The Iron Webmaster, 30

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The problem is easy if you limits your desires to one or more of the following:
    1) Have collision avoidance, where a flock of particles each exert a
REPULSIVE FORCE on each other;
    2) Have a particle STEER to find lower-collision-probability directions for
travel;
    3) Have one particle be treated as a point, with no limits on the complexity,
concavity, tortuosity, etc., of the object it collides into.

I have examples of all of these on my page (which BTW might not be functional as
of this hour) at:


Matt Giwer wrote:

> GrimDude wrote:
> >
> > Has anyone done anything like this?
>
>         If you remember that collision detection is an exhaustive test, yes,
> lots of people have done it. Collision detection in game machines are
> dedicated sprites and colligion registers or are background parallel
> routines in machines without collision registers.
>
>         If you are going to drop random sized and shaped things into your POV
> file rotsa ruck on finding a fast was to avoid collisions.
>
>         There are plenty of strategies for it depending upon what you have in
> mind.
>
> --
> The US fought Germany in WWII because Germany
> declared war on the US.
>         -- The Iron Webmaster, 30

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http://members.xoom.com/gregjohn/animation.html

Yes, it is a great headache to calculate true collisions between:
    1) complex object A and complex object B
    2) three rigid objects ( _This_ is why a perfect billiard simulation is
difficult).

"Greg M. Johnson" wrote:

> I have examples of all of these on my page (which BTW might not be functional as
> of this hour) at:
>
> Matt Giwer wrote:
>
> >         If you are going to drop random sized and shaped things into your POV
> > file rotsa ruck on finding a fast was to avoid collisions.

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