[Bf-funboard] Particles system rewrite?
bf-funboard@blender.org
bf-funboard@blender.org
Thu, 14 Aug 2003 11:35:22 -0500
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=09
Incredible. However, I'm not sure how this could be implemented. One
thing to notice, all his particles are clearly visible in the =
renderings. In
other words, it looks like tapioca pudding (for those who don't have a =
clue
what this is, don't worry about it). It would defiantly have to use
meta-balls if used in blender. Something to think about though.
Timothy=20
-----Original Message-----
From: Gregor M=FCckl [mailto:GregorMueckl@gmx.de]
Sent: Thursday, August 14, 2003 9:11 AM
To: bf-funboard@blender.org
Subject: Re: [Bf-funboard] Particles system rewrite?
Hi!
Just let me throw in a remark on a dedicated simulation program for =
fluids=20
that a (really brilliant) guy did for school:
http://falmaidan.sourceforge.net
[Now the author of this program is studying physics with me :-)]
This program does not simulate a particle system but does the =
"classical"=20
approach of solving the Navier-Stokes differential equations for fluids =
to=20
achieve this. And please note that the fluid was not rendered using=20
(better-looking) blobs because POV-ray had a strange bug that prevented
this.
My point is that the suggestion to use particles for simulating fluids =
is a=20
bad one because fluid dynamics are rather complex. Use a dedicated
simulation=20
for that.
Particular problems I see with particle-based fluid sims are the =
following:
1. How do you prevent particles from bouncing back and leaving the =
fluid and
thus forming isolated droplets when they shouldn't?
2. What about performance? Calculating particle densities is a =
performance=20
killer and having individual particles obey the laws of physics (and =
even if
it's only a simple application of Newton's laws) this is really slow =
even
for=20
relatively small numbers of particles. I tried to do such a simulation =
some=20
time ago and failed.
Dedicated simulations will be a lot faster as the math already accounts =
for=20
the accumulated effects of individual particles.
Regards,
Gregor
Am Mittwoch, 13. August 2003 19:53 schrieb Jonathan Bartlett:
> here's some crazy thoughts, but they would be fun if they weren't a
> nightmare to implement:
>
> Particle physics - have the ability for particles to obey physics =
laws of
> other dynamic objects, whenever we get our dynamics engine back.
>
> Maximum particle density - This way, you could animate pouring water =
to
> fill a glass - the particles follow physics on their way down and =
then
> "fill" the glass, based on particle density.
>
> Jon
>
> On Wed, 13 Aug 2003 tbaldridge@alertacademy.com wrote:
> > First, I need to explain something. The link I gave to PPFX needs =
a
> > disclaimer on it. I am not suggesting by any means, that we need to =
port
> > PPFX. PPFX, is a post processing plug-in that analyzes the Z-buffer =
of
> > the rendered image, and uses it to decide how to render the =
particles.
> > So, basically, I'm suggesting that we keep the rendering part of =
the
> > current system, but update the calculation code to add the =
following
> > features:
> >
> > 1. Vortexes
> > 2. Jitter value for almost every value
> > 3. Key framing for all values
> > 4. The amount of particles be based on a "flow" value, and not on =
an
> > absolute one (the value would represent about of particles released
every
> > frame, not the total amount of particles in the system)
> > 5. Uniform distribution of particles (a large face will emit more
> > particles than a smaller one in the same object)
> > 6. Gravitons, Fans, etc.
> >
> >
> > I'm perfectly willing to help code this. Currently, I'm busy =
working
> > on cloth support, but I will be glad to help in any way I can.
> >
> > Timothy
> >
> >
> > -----Original Message-----
> > From: Ton Roosendaal [mailto:ton@blender.org]
> > Sent: Wednesday, August 13, 2003 8:20 AM
> > To: bf-funboard@blender.org
> > Subject: Re: [Bf-funboard] Particles system rewrite?
> >
> >
> > Hi,
> >
> > This system works completely different from Blender, and its =
'features
> > and limitations' page is quite disturbing... however, it does =
support
> > quite some more motion systems.
> >
> > A proposal for a 'rewrite' can only be evaluated if you think =
someone's
> > going to do the coding and technical design for it.
> >
> > If a discussion can be limited to defining a couple of features =
that we
> > see missing, then I can at least advise on what the feasibility is =
to
> > improve/adjust the current implementation.
> >
> > -Ton-
> >
> >
> > On Tuesday, Aug 12, 2003, at 22:39 Europe/Amsterdam,
> >
> > tbaldridge@alertacademy.com wrote:
> > > =20
> > > What about a complete rewrite of the particles system? It =
is
> > > good, but there need to be some changes. For instance, how about =
a
> > > vortex value that allows the user to crate a swirl in the =
particles.
> > > Another idea, is the ability every value in the system to have a
> > > "jitter" value. Basically I'm pattering this idea off of the =
trueSpace
> > > plug-in Primal Particles FX. Here is a link to the on-line
> > > documentation that will give you an idea of what I'm talking =
about:
> > >
> > > http://www.primitiveitch.com/ppfx/docs/index.html
> > >
> > > What do you think?
> > >
> > > Timothy
> >
> > =
------------------------------------------------------------------------=
> > --
> > Ton Roosendaal Blender Foundation ton@blender.org
> > http://www.blender.org
> >
> > _______________________________________________
> > Bf-funboard mailing list
> > Bf-funboard@blender.org
> > http://www.blender.org/mailman/listinfo/bf-funboard
>
> _______________________________________________
> Bf-funboard mailing list
> Bf-funboard@blender.org
> http://www.blender.org/mailman/listinfo/bf-funboard
_______________________________________________
Bf-funboard mailing list
Bf-funboard@blender.org
http://www.blender.org/mailman/listinfo/bf-funboard
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<P> =20
<BR> <FONT =
SIZE=3D2>Incredible. However, I'm not sure how this could be =
implemented. One thing to notice, all his particles are clearly visible =
in the renderings. In other words, it looks like tapioca pudding (for =
those who don't have a clue what this is, don't worry about it). It =
would defiantly have to use meta-balls if used in blender. Something to =
think about though.</FONT></P>
<P> =
<FONT SIZE=3D2>Timothy =
</FONT>
</P>
<P><FONT SIZE=3D2>-----Original Message-----</FONT>
<BR><FONT SIZE=3D2>From: Gregor M=FCckl [<A =
HREF=3D"mailto:GregorMueckl@gmx.de">mailto:GregorMueckl@gmx.de</A>]</FON=
T>
<BR><FONT SIZE=3D2>Sent: Thursday, August 14, 2003 9:11 AM</FONT>
<BR><FONT SIZE=3D2>To: bf-funboard@blender.org</FONT>
<BR><FONT SIZE=3D2>Subject: Re: [Bf-funboard] Particles system =
rewrite?</FONT>
</P>
<BR>
<P><FONT SIZE=3D2>Hi!</FONT>
</P>
<P><FONT SIZE=3D2>Just let me throw in a remark on a dedicated =
simulation program for fluids </FONT>
<BR><FONT SIZE=3D2>that a (really brilliant) guy did for school:</FONT>
</P>
<P><FONT SIZE=3D2><A HREF=3D"http://falmaidan.sourceforge.net" =
TARGET=3D"_blank">http://falmaidan.sourceforge.net</A></FONT>
</P>
<P><FONT SIZE=3D2>[Now the author of this program is studying physics =
with me :-)]</FONT>
</P>
<P><FONT SIZE=3D2>This program does not simulate a particle system but =
does the "classical" </FONT>
<BR><FONT SIZE=3D2>approach of solving the Navier-Stokes differential =
equations for fluids to </FONT>
<BR><FONT SIZE=3D2>achieve this. And please note that the fluid was not =
rendered using </FONT>
<BR><FONT SIZE=3D2>(better-looking) blobs because POV-ray had a strange =
bug that prevented this.</FONT>
</P>
<P><FONT SIZE=3D2>My point is that the suggestion to use particles for =
simulating fluids is a </FONT>
<BR><FONT SIZE=3D2>bad one because fluid dynamics are rather complex. =
Use a dedicated simulation </FONT>
<BR><FONT SIZE=3D2>for that.</FONT>
</P>
<P><FONT SIZE=3D2>Particular problems I see with particle-based fluid =
sims are the following:</FONT>
</P>
<P><FONT SIZE=3D2>1. How do you prevent particles from bouncing back =
and leaving the fluid and </FONT>
<BR><FONT SIZE=3D2>thus forming isolated droplets when they =
shouldn't?</FONT>
</P>
<P><FONT SIZE=3D2>2. What about performance? Calculating particle =
densities is a performance </FONT>
<BR><FONT SIZE=3D2>killer and having individual particles obey the laws =
of physics (and even if </FONT>
<BR><FONT SIZE=3D2>it's only a simple application of Newton's laws) =
this is really slow even for </FONT>
<BR><FONT SIZE=3D2>relatively small numbers of particles. I tried to do =
such a simulation some </FONT>
<BR><FONT SIZE=3D2>time ago and failed.</FONT>
</P>
<P><FONT SIZE=3D2>Dedicated simulations will be a lot faster as the =
math already accounts for </FONT>
<BR><FONT SIZE=3D2>the accumulated effects of individual =
particles.</FONT>
</P>
<P><FONT SIZE=3D2>Regards,</FONT>
<BR><FONT SIZE=3D2>Gregor</FONT>
</P>
<P><FONT SIZE=3D2>Am Mittwoch, 13. August 2003 19:53 schrieb Jonathan =
Bartlett:</FONT>
<BR><FONT SIZE=3D2>> here's some crazy thoughts, but they would be =
fun if they weren't a</FONT>
<BR><FONT SIZE=3D2>> nightmare to implement:</FONT>
<BR><FONT SIZE=3D2>></FONT>
<BR><FONT SIZE=3D2>> Particle physics - have the ability for =
particles to obey physics laws of</FONT>
<BR><FONT SIZE=3D2>> other dynamic objects, whenever we get our =
dynamics engine back.</FONT>
<BR><FONT SIZE=3D2>></FONT>
<BR><FONT SIZE=3D2>> Maximum particle density - This way, you could =
animate pouring water to</FONT>
<BR><FONT SIZE=3D2>> fill a glass - the particles follow physics on =
their way down and then</FONT>
<BR><FONT SIZE=3D2>> "fill" the glass, based on particle =
density.</FONT>
<BR><FONT SIZE=3D2>></FONT>
<BR><FONT SIZE=3D2>> Jon</FONT>
<BR><FONT SIZE=3D2>></FONT>
<BR><FONT SIZE=3D2>> On Wed, 13 Aug 2003 tbaldridge@alertacademy.com =
wrote:</FONT>
<BR><FONT SIZE=3D2>> > First, I need to =
explain something. The link I gave to PPFX needs a</FONT>
<BR><FONT SIZE=3D2>> > disclaimer on it. I am not suggesting by =
any means, that we need to port</FONT>
<BR><FONT SIZE=3D2>> > PPFX. PPFX, is a post processing plug-in =
that analyzes the Z-buffer of</FONT>
<BR><FONT SIZE=3D2>> > the rendered image, and uses it to decide =
how to render the particles.</FONT>
<BR><FONT SIZE=3D2>> > So, basically, I'm suggesting that we keep =
the rendering part of the</FONT>
<BR><FONT SIZE=3D2>> > current system, but update the calculation =
code to add the following</FONT>
<BR><FONT SIZE=3D2>> > features:</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > 1. Vortexes</FONT>
<BR><FONT SIZE=3D2>> > 2. Jitter value for =
almost every value</FONT>
<BR><FONT SIZE=3D2>> > 3. Key framing for all =
values</FONT>
<BR><FONT SIZE=3D2>> > 4. The amount of =
particles be based on a "flow" value, and not on an</FONT>
<BR><FONT SIZE=3D2>> > absolute one (the value would represent =
about of particles released every</FONT>
<BR><FONT SIZE=3D2>> > frame, not the total amount of particles =
in the system)</FONT>
<BR><FONT SIZE=3D2>> > 5. Uniform distribution =
of particles (a large face will emit more</FONT>
<BR><FONT SIZE=3D2>> > particles than a smaller one in the same =
object)</FONT>
<BR><FONT SIZE=3D2>> > 6. Gravitons, Fans, =
etc.</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > I'm perfectly willing =
to help code this. Currently, I'm busy working</FONT>
<BR><FONT SIZE=3D2>> > on cloth support, but I will be glad to =
help in any way I can.</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > =
Timothy</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > -----Original Message-----</FONT>
<BR><FONT SIZE=3D2>> > From: Ton Roosendaal [<A =
HREF=3D"mailto:ton@blender.org">mailto:ton@blender.org</A>]</FONT>
<BR><FONT SIZE=3D2>> > Sent: Wednesday, August 13, 2003 8:20 =
AM</FONT>
<BR><FONT SIZE=3D2>> > To: bf-funboard@blender.org</FONT>
<BR><FONT SIZE=3D2>> > Subject: Re: [Bf-funboard] Particles =
system rewrite?</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > Hi,</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > This system works completely different =
from Blender, and its 'features</FONT>
<BR><FONT SIZE=3D2>> > and limitations' page is quite =
disturbing... however, it does support</FONT>
<BR><FONT SIZE=3D2>> > quite some more motion systems.</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > A proposal for a 'rewrite' can only be =
evaluated if you think someone's</FONT>
<BR><FONT SIZE=3D2>> > going to do the coding and technical =
design for it.</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > If a discussion can be limited to defining =
a couple of features that we</FONT>
<BR><FONT SIZE=3D2>> > see missing, then I can at least advise on =
what the feasibility is to</FONT>
<BR><FONT SIZE=3D2>> > improve/adjust the current =
implementation.</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > -Ton-</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > On Tuesday, Aug 12, 2003, at 22:39 =
Europe/Amsterdam,</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > tbaldridge@alertacademy.com wrote:</FONT>
<BR><FONT SIZE=3D2>> > =
> </FONT>
<BR><FONT SIZE=3D2>> > =
> What about a =
complete rewrite of the particles system? It is</FONT>
<BR><FONT SIZE=3D2>> > > good, but there need to be some =
changes. For instance, how about a</FONT>
<BR><FONT SIZE=3D2>> > > vortex value that allows the user to =
crate a swirl in the particles.</FONT>
<BR><FONT SIZE=3D2>> > > Another idea, is the ability every =
value in the system to have a</FONT>
<BR><FONT SIZE=3D2>> > > "jitter" value. Basically =
I'm pattering this idea off of the trueSpace</FONT>
<BR><FONT SIZE=3D2>> > > plug-in Primal Particles FX. Here is =
a link to the on-line</FONT>
<BR><FONT SIZE=3D2>> > > documentation that will give you an =
idea of what I'm talking about:</FONT>
<BR><FONT SIZE=3D2>> > ></FONT>
<BR><FONT SIZE=3D2>> > > <A =
HREF=3D"http://www.primitiveitch.com/ppfx/docs/index.html" =
TARGET=3D"_blank">http://www.primitiveitch.com/ppfx/docs/index.html</A><=
/FONT>
<BR><FONT SIZE=3D2>> > ></FONT>
<BR><FONT SIZE=3D2>> > =
> What do you =
think?</FONT>
<BR><FONT SIZE=3D2>> > ></FONT>
<BR><FONT SIZE=3D2>> > =
> &n=
bsp; Timothy</FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > =
------------------------------------------------------------------------=
</FONT>
<BR><FONT SIZE=3D2>> > --</FONT>
<BR><FONT SIZE=3D2>> > Ton Roosendaal Blender Foundation =
ton@blender.org</FONT>
<BR><FONT SIZE=3D2>> > <A HREF=3D"http://www.blender.org" =
TARGET=3D"_blank">http://www.blender.org</A></FONT>
<BR><FONT SIZE=3D2>> ></FONT>
<BR><FONT SIZE=3D2>> > =
_______________________________________________</FONT>
<BR><FONT SIZE=3D2>> > Bf-funboard mailing list</FONT>
<BR><FONT SIZE=3D2>> > Bf-funboard@blender.org</FONT>
<BR><FONT SIZE=3D2>> > <A =
HREF=3D"http://www.blender.org/mailman/listinfo/bf-funboard" =
TARGET=3D"_blank">http://www.blender.org/mailman/listinfo/bf-funboard</A=
></FONT>
<BR><FONT SIZE=3D2>></FONT>
<BR><FONT SIZE=3D2>> =
_______________________________________________</FONT>
<BR><FONT SIZE=3D2>> Bf-funboard mailing list</FONT>
<BR><FONT SIZE=3D2>> Bf-funboard@blender.org</FONT>
<BR><FONT SIZE=3D2>> <A =
HREF=3D"http://www.blender.org/mailman/listinfo/bf-funboard" =
TARGET=3D"_blank">http://www.blender.org/mailman/listinfo/bf-funboard</A=
></FONT>
</P>
<P><FONT =
SIZE=3D2>_______________________________________________</FONT>
<BR><FONT SIZE=3D2>Bf-funboard mailing list</FONT>
<BR><FONT SIZE=3D2>Bf-funboard@blender.org</FONT>
<BR><FONT SIZE=3D2><A =
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