Open Simulator with Physics Engine

[cafl at msbit.com]

http://edu.kde.org/step/index.php
This was apparently finished during 2007 google summer of code

Description

Step is an interactive physical simulator. It works like this: you
place some bodies on the scene, add some forces such as gravity or
springs, then click "Simulate" and Step shows you how your scene will
evolve according to the laws of physics. You can change every property
of bodies/forces in your experiment (even during simulation) and see
how this will change evolution of the experiment. With Step you can
not only learn but feel how physics works !
Features

    * Classical mechanical simulation in two dimensions
    * Particles, springs with dumping, gravitational and coulomb forces
    * Rigid bodies
    * Collision detection (currently only discrete) and handling
    * Soft (deformable) bodies simulated as user-editable
particles-springs system, sound waves
    * Molecular dynamics (currently using Lennard-Jones potential):
gas and liquid, condensation and evaporation, calculation of
macroscopic quantities and their variances
    * Units conversion and expression calculation: you can enter
something like "(2 days + 3 hours) * 80 km/h" and it will be accepted
as distance value (requires libqalculate)
    * Errors calculation and propagation: you can enter values like
"1.3 ± 0.2" for any property and errors for all dependent properties
will be calculated using statistical formulas
    * Solver error estimation: errors introduced by the solver is
calculated and added to user-entered errors
    * Several different solvers: up to 8th order, explicit and
implicit, with or without adaptive timestep (most of the solvers
require GSL library)
    * Controller tool to easily control properties during simulation
(even with custom keyboard shortcuts)
    * Tools to visualize results: graph, meter, tracer
    * Context information for all objects, integrated wikipedia browser
    * Collection of example experiments, more can be downloaded with KNewStuff2

StepCore Library

StepCore is the physical simulation library on which Step is based. It
can be used without Step for complex simulations which require coding
or in other software which require physical simulation functionality.
It is designed in order to be extensible, tunable and to provide
accurate simulation.


On 2/15/08, Jeremy Fitzhardinge <jeremy at goop.org> wrote:
> Edward Cherlin wrote:
> > Has anybody looked at this for the XO?
> >
> > http://opensimulator.org/wiki/PhysicsEngines
> >
> > The physics is not very realistic yet. Presumably we could manage
> > simple statics and dynamics, with graphs of position, velocity, and
> > acceleration.
> >
> > I would like to have a simulation engine available for integration
> > into e-textbooks. What other candidates are there?
> >
> >
>
> I've been looking at using Chipmunk (a 2D physics library:
> http://wiki.slembcke.net/main/published/Chipmunk) to do a simple
> activity which allows the user to draw shapes freehand, and then have
> them physically simulated.  By choosing different pens, you can draw
> either fixed, rigid or flexible shapes.  People have already developed
> similar programs using chipmunk, and the demo videos are very
> interesting.  Unfortunately they seem to be under closed licenses.
> Besides, a Sugar version would be most interesting with some kind of
> mesh multiuser component, which would probably significantly change how
> the program evolves.
>
> I've done some very early prototypes on the XO, mostly by running the
> Chipmunk test program.  It was surprisingly slow; I looked at optimising
> chipmunk to use 3dnow, but I suspect the bottleneck is in actually
> rendering (I have not profiled it properly).  I was hoping to use Cairo
> for rendering, but it seems to be a bit too slow for smooth animated
> rendering.
>
> I was hoping to put together and announce something simple for people to
> poke at in the next week or two.
>
>     J
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>


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