magnetic sim

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magnetic sim

Post by Mark62756 » Fri Dec 26, 2008 7:11 pm

Hey all, I wasn't quite sure on where to ask this question so sorry if it is in the wrong forum. I've been wondering and interested in doing some studies with magnets. Or mainly electric motors (AC and DC and such.) I was wondering if it were possible to be able to kinda accurately simulate how they work in bullet or if there is something else that would do the job. I'm just looking for someone to point me in the right direction.

As I write this I am thinking of a way to be able to do it in blender. By controlling the phase forces(i guess?) with python. Could be easier ways. Let me know what you think. And thanks.


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Joined: Sun Jul 10, 2005 9:48 pm
Location: NJ, USA

Re: magnetic sim

Post by Mark62756 » Fri Jan 09, 2009 1:56 am

guess no ideas? :\ so many views, no posts.

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Re: magnetic sim

Post by efoss » Fri Jan 09, 2009 8:55 pm

I think the problem is that most people on this forum are knowledgeable mainly about mechanical simulation, with perhaps some fluid simulation thrown in.

On the other hand, I'm sure some of us have some memory of magnetism physics from school. You would probably also need to simulate electrical flow for the examples you cited. Maybe there is some electrical simulation software which is also capable of doing the magnetics you describe. I found this article which seems like someone was trying to solve magnetic problems with PSpice, but it is not clear how well this will help with your problem.

Hopefully someone else here will have a better suggestion.


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Re: magnetic sim

Post by Nathanael » Sat Jan 10, 2009 8:21 am

Have a look here: ... otion.html

Good luck,

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Re: magnetic sim

Post by Sione » Sat Jan 17, 2009 10:37 pm

im afraid general physics engine such as bullet, havok and physx can not help you much. they are mostly about COLLISION DETECTION. they are about moving objects at their speed and monitoring if they have collided with something. collision response is still mainly up to you.

it seems to me, what you need is Maxwell equations or similar E/M FIELD equations. in other words, once you implement magneto-electric fields interaction it will automatically handle both "collision and response", its built-in into those equations, so to say.

if you would like to simulate electrons and protons as a collection of charged particles, each with its mass, velocity, charge and magneto-electric dipole field, then you need Lorentz equations and you may contact me here if that is the case, i'll share some source code:

my only problem is SPIN... now, instead of starting a new thread let me ask my question here and hopefully it is related to original question, so here it goes...

--- THREE MAGNETS (N-dipole-body problem) ---
imagine 3 bar magnets sitting on a table randomly spaced. they are fixed and can not translate, only rotate around their centers , it is 2D situation. there is no gravity, no friction and only forces are magnetic forces. here is a picture where "x" is the point of rotation and coordinate center of each magnet, we have "top" magnet, "middle" magnet and "bottom", like this:

Code: Select all

[S- x -N]                                topMag: a=90, x=7, y=25

                  [N- x -S]              midMag: a=270, x=18, y=19

      [S- x -N]                          botMag: a=90, x=12, y=4
- input are 3 initial angles and 3 pairs of (x,y) coordinates
- output are the new angles after system stabilize

1.) is there a "general solution" or it must be integrated step by step?
2.) is there a singe solution? is solution stable, chaotic or oscillating?

basically, how to simulate this simple situation?

unfortunately it does not end there. this is only simplified situation and "real algorithm" is the one that can handle situations in 3D with any number of "free floating" magnetic dipoles. it will need to handle both angular and linear acceleration. however, even if this is possible the ultimate question is still how to compare it with the real-world and make sure there are no bugs. here's simple question from every day life: given the four situations - DO MAGNETS ATTRACT OBJECTS IN A STRAIGHT LINE??

a.) magnet dipole - magnet dipole
b.) magnet dipole - electric charge
c.) magnet dipole - metal molecule
d.) magnet dipole - charged metal molecule

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Re: magnetic sim

Post by Magneto » Mon Apr 07, 2014 12:55 pm

Hey Sione,
Did you get any solution to the problem you descibed above?
I am also stuck with something like this.
In my case I have to simulate the motion of magnets their collision force and tourque.

Consider a bar magnets (N==S) inside a plastic coin or disk and now we have 3 or four such coin. Give initial push to one of the coin. now I have to simulate the behaviour. I tried blender but not much success. Can you help me. Have some source code? I was trying it in python with blender.

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