Here's my newest test-animation.

The metal tube is a CSG-Spline made
of spheres and cylinders. The Spline was
calculated using a Bezier-Spline-Algorithm
I implemented myself.

The Particles are emitted from the designated
Spline and are forced outwards due to centrifugal
forces.

Actually, I implemented an algorithm to calculate
a centrifugal-force on a given Bezier-Curve. This
was not that easy, since I had to adjust the algorithm
to not try to calculate a position after or before the
defined spline (when thinking in values of 0 to 1,
-.1 and 1.1 aren't allowed, simple as that).
Also, when the calculations made in detail seem to
result in no centrifuge on a bezier-spline, the
algorithm expects that the intervals had been taken
too small and increases them.

Another new addition running in the background
of the system is to leave particles out of calculation
process. I hadn't implemented it beforehand, simply
because it escaped my mind that I could have a
new random-stream for every particle.

So, these are 250 frames, with about 10sec parsing
and 25 secs tracing per frame, with up to 400
particles, 250 spheres and 250 cylinders, along with
a media-sphere for the glow-effect, a lightsource
and the camera. Due to tracing interruptions (never
trace and modify the code when using random-streams)
I can't tell the overall time of parsing and tracing.
(Oh: 1.4 GHZ, 512 MB Ram, Win98)

Comments? (Aside that I should have used more particles
to make it look more like a cloud than individuals)

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html

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Attachments:
Download 'centri.mpg' (331 KB)

YAY! my first video file on linux (and mplayer seemed a good choice(?)

looks very sweet :)

-- 
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Rick

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Neat! I actually kind of like the individual particles instead of a cloud-
makes it look like some kind of magic ;)

"Tim Nikias" <tim### [at] gmxde> wrote in message
news:3C8B988F.9FF48E11@gmx.de...
> Here's my newest test-animation.
>
> The metal tube is a CSG-Spline made
> of spheres and cylinders. The Spline was
> calculated using a Bezier-Spline-Algorithm
> I implemented myself.
>
> The Particles are emitted from the designated
> Spline and are forced outwards due to centrifugal
> forces.
>
> Actually, I implemented an algorithm to calculate
> a centrifugal-force on a given Bezier-Curve. This
> was not that easy, since I had to adjust the algorithm
> to not try to calculate a position after or before the
> defined spline (when thinking in values of 0 to 1,
> -.1 and 1.1 aren't allowed, simple as that).
> Also, when the calculations made in detail seem to
> result in no centrifuge on a bezier-spline, the
> algorithm expects that the intervals had been taken
> too small and increases them.
>
> Another new addition running in the background
> of the system is to leave particles out of calculation
> process. I hadn't implemented it beforehand, simply
> because it escaped my mind that I could have a
> new random-stream for every particle.
>
> So, these are 250 frames, with about 10sec parsing
> and 25 secs tracing per frame, with up to 400
> particles, 250 spheres and 250 cylinders, along with
> a media-sphere for the glow-effect, a lightsource
> and the camera. Due to tracing interruptions (never
> trace and modify the code when using random-streams)
> I can't tell the overall time of parsing and tracing.
> (Oh: 1.4 GHZ, 512 MB Ram, Win98)
>
> Comments? (Aside that I should have used more particles
> to make it look more like a cloud than individuals)
>
> --
> Tim Nikias
> Homepage: http://www.digitaltwilight.de/no_lights/index.html
>
>

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Looks good, and I bet the emitting media rendered alot faster than scattering smoke.

MJL

--
prism{0,.1,30#local I=1;#while(I<30)#local B=asc(substr(// Mark James Lewin
"#K?U_u`V[RG>3<9DGPL.0EObkcPF'",I,1))-33;<div(B,10)-4mod(B,10)+5*div(I,21)-
6>#local I=I+1;#end,-4pigment{rgb 9}rotate-x*90translate 15*z}//POV-Ray 3.5

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> Looks good, and I bet the emitting media rendered alot faster than scattering smoke.
>

Thanks. Yes, it did significantly (25secs in comparison to 1 min or so).

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html

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> Neat! I actually kind of like the individual particles instead of a cloud-
> makes it look like some kind of magic ;)

There is no magic involved, only POV-Ray SDL and over
a year in algorithmic trial/error + logic thinking...

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html

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Thanks.


> looks very sweet :)
>

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html

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"Tim Nikias" wrote:
> Here's my newest test-animation.

That's a nice effect!

However, I'm not sure what the purpose of the metal tube is. Is it supposed
to be a real object or just a visualizasion of the path that the white glow
is taking? Is it the tube that's the emitter or is it the white glow? If the
tube is the emitter, then what is the white glow, and if the white glow is
the emitter, then what is the tube? Maybe you could take basis in some
example from real life.

If the white glow is the emitter, then there might be a flaw in the inertia
design of the particles, because then inertia should have effect for all
movements of the white glow, not just the global rotation.

I'm not sure I exaplin very well what I mean, but it would be easier if you
took basis in some situation from real life.

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:    http://rsj.mobilixnet.dk (updated Feb 16)
POV-Ray Users:   http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Webring: http://webring.povray.co.uk

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>
> That's a nice effect!
>

Thanks!

>
> However, I'm not sure what the purpose of the metal tube is. Is it supposed
> to be a real object or just a visualizasion of the path that the white glow
> is taking? Is it the tube that's the emitter or is it the white glow? If the
> tube is the emitter, then what is the white glow, and if the white glow is
> the emitter, then what is the tube? Maybe you could take basis in some
> example from real life.
>

Well, okay. The white glow emits the particles.
The glow moves along the silver tube, which is there
for visualization. The camera rotates around the scene to
show more clearly how the particles fly.


>
> If the white glow is the emitter, then there might be a flaw in the inertia
> design of the particles, because then inertia should have effect for all
> movements of the white glow, not just the global rotation.
>

I don't know if I understand these sentences. What the
system did was to calculate in which direction the
centrifugal-force would go, given a large enough speed.
This direction is in no means proportional to any actual
speed (yet), but just normalized and used for the
particles to fly somewhere.

>
> I'm not sure I exaplin very well what I mean, but it would be easier if you
> took basis in some situation from real life.
>

Take a glass of water, drive a car, open the window, and hold
the glass outside. When driving through a curve, the water
might drift off outwards.
Sadly, glasses of water aren't easily created with particles.
But for the Release I'll come up with a better example,
I promise! ;-)

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html

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"Tim Nikias" wrote:
> Well, okay. The white glow emits the particles.
> The glow moves along the silver tube, which is there
> for visualization.

Ah, that's what I thought.

> I don't know if I understand these sentences.
> What the system did was to calculate in which
> direction the centrifugal-force would go, given
> a large enough speed.

But a centrifugal force is just the force of inertia.

> Take a glass of water, drive a car, open the window,
> and hold the glass outside. When driving through a
> curve, the water might drift off outwards.

Exactly, because of inertia. First the car drives North. When it turns and
drives East, the water still moves in the North direction, which is now
outwards from the perpective of the car. It looks like the water moves
outwards, but it actually just moves in the same direction it did all the
time.

My point is that all movements of the emitter should affect interia, not
just the overall rotation of the metal tube.

In your animation it's like the whole metal tube is the car, so the rotation
of the metal tube causes a centrifugal force. However, it is really not the
tube that's the car, it is only the white glow that is the car, and the tube
is like the road that the car is driving on (ok, a rotating road, but
still.) Every turn the white glow takes on the spline should have a
centrifugal force, not just the overall rotation of the metal tube.

Is it more clear now what I mean?

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:    http://rsj.mobilixnet.dk (updated Feb 16)
POV-Ray Users:   http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Webring: http://webring.povray.co.uk

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