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Hi,
Seeing the latest mechsim animations I just could not resist
and made a domino sequence without using the mech-sim patch.
Although I admire the funny cartoonesk way the spring powered blocks
behave and I cannot even imagine how much it took to program this into
a raytracer (a great job !!), I think this is not a good solution for
doing mechnical simulations.
You can do these kind of things much faster, more accurate and without
the risk of crashing your raytracer with external modellers and
simulators.
But the main reason for me is speed and reliability,
because I am lazy : I made this in 5 minutes with Xaero
and it took another 5 minutes to trace 140 frames at 640x480 A0.3
and to compile a movie.
Mechanical simulators can be found at:
www.q12.org : ODE Status: Alive and active
http://www.aero-simulation.de/ Status: Dead ??
Willem
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Post a reply to this message
Attachments:
Download 'dom_mjpeg_320.m1v.mpg' (775 KB)
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Post a reply to this message
Attachments:
Download 'dom_mjpeg_320.m1v.mpg' (462 KB)
Download 'domstack2.world.txt' (8 KB)
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Why does the pyramid of dominos seem to take a breath at the beginning?
-DJ
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>Why does the pyramid of dominos seem to take a breath at the beginning?
>
>-DJ
Because it is afraid of what is coming...
or
My fault, I probably did not stack all the dominos at the correct
position, so they fall to their correct position, or are pushed up by
the modeller if the two blocks are overlapping
Willem
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Looks nice, but if it's not done with POV, I doubt it's faster and more
flexible. Only if you don't need POV's features!
I see the link you gave to the "ODE" is freeware and that's very nice, but
worlds in POV-Ray are rarely made of polygons and therefore can't be
exported to other programs. A POV-Ray user usually tries to visualise things
in his head, and then write the code. This is entirely different from
actually seeing the visualisation and trying to understand what's going on.
Generally, it's not easier for me to switch between several programs.. It
complicates the process a lot.. I think the mechsim in POV-Ray is going to
be a key feature in the future.. However, if the "ODE" is really free maybe
it's features could be ported to POV.
Regards,
Hugo
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On Mon, 10 Feb 2003 14:38:44 +0100, Christoph Hormann
<chr### [at] gmx de> wrote:
> I cannot even imagine how much it took to program this into
> a raytracer (a great job !!),
I mean this, a complement well deserved.
>Feel free to think whatever you want to think but i see no argument in
>your writing that would support this extremely general statement.
Ok, might be too general, see more nuance below
>> You can do these kind of things much faster, more accurate and without
>> the risk of crashing your raytracer with external modellers and
>> simulators.
>
>This strongly indicates that you don't really know what you are talking
>about.
Statements like this will not really engage people in a
discussion..... Plenty of managers in high tech company's pay loads of
money to send their engineers to courses in order to train them not to
make this kind of statements. Trust me on this.
>First of all the mechsim patch is not any more likely to crash
>POV-Ray than any other experimental feature.
True, but I am not comparing with other POV features, I am comparing
with mechanical simulation systems which have, as you know, lots of
mathematical appoximations and in this case "spring & damper" systems
which are inherently unstable when used without extreme caution.
These should not be part of a renderer which should just render any
datafile whe feed it.
>And then i have serious
>doubts that Aero is substantially faster or more accurate simulating the
>same system than the mechsim patch.
From an end-user perspective it certainly was :), it really took
me just a couple of minutes. You give the reason below; I did have the
need the build objects from point masses and to apply the "correct"
stiffness factors. Wooden domino blocks do not bend or deform
when they fall. That is what triggered me in the first place.
Could we compare ? i.e. create a sample scene, a sort of a skyvase
for mechsim and compare on speed an accuracy ? See where the limits
are ?
>What probably makes Aero more appealing to you is the ability to simulate
>the movement of a few basic shapes like boxes and cylinders without the
>necessity to build them from point masses like in mechsim.
Look what it is used for by the other users; they use it for modelling
the behaviour of in-flexible masses, like domino blocks, or balls
falling down a wall filled with obstacles.
Yes I like the simplification approach. Simulation simplified models
correctly gives i.m.h.o. better results than larger, unstable, models.
But maybe recent models and CPU power are catching up on me.
>have a look at the Aero documentation you will recognize that there is a
>serious number of tricks necessary to make this work. This might produce
>reasonable results for falling domino stones but will break into pieces as
>soon as you try a simulation of more complex shapes and deformable bodies.
I know the limitations of aero and the tricks. Deformable bodies are
the holy grail of course. Can you do this ? Can you make a cube which
falls on a corner and actually deforms permanently ?
>BTW animations posted in several pieces will be difficult to view for a
>lot of people.
>Christoph
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> These should not be part of a renderer which should
> just render any datafile whe feed it.
In other words, we could remove half of POV-Ray because it's not very
useful? On the other hand, this is what makes POV-Ray unique.
I predict that in 10 years, Hollywood will use POV-Ray to model and raytrace
everything in their films. The studios will even use it to make coffee.
Moreover, it will replace ICQ and people will communicate through POV-Ray.
The operating system on most computers will be POV based.. well you get the
idea.. ;o) It might be overdriven but POV-Ray is not just a raytracer. It's
already being developed as a programming language, and no experiments are
really useless. It will be interesting to see where the mechsim will go.
But thanks for your input. Of course there will be different opinions, and
we can probably learn something from everyone.
Regards,
Hugo
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>But thanks for your input. Of course there will be different opinions, and
>we can probably learn something from everyone.
That why they are opinions :)
Just one example: MsWord used to fit on a couple of floppies.....
It has much more functionality now, but is it better ?
Willem
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On Mon, 10 Feb 2003 16:45:37 +0100, Willem
<willem_dot_de_dot_wilde_at_xs4all.nl> wrote:
> Just one example: MsWord used to fit on a couple of floppies.....
> It has much more functionality now, but is it better ?
Actually MegaPOV 1.0 for DOS fits perfectly on one 1,44 floppy :-)
http://megapov.inetart.net/download.html
ABX
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