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Shashi

Rigid body dynamics tutorials

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I need a good rigid body dynamics tutorial. I just finished my year 12 calculus course, so its all pretty fresh in my mind. Practically all the tutorials and papers I've looked up on the net confused me alot. Does anyone know of a tutorial on the subject that isn't overtly technical?

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The usual: Hecker and Baraff. If those are among the materials you've found confusing, you might explain what it is you're unsure of. There are many people on this forum who could probably help clear things up for you, or point you to other references that might fill in some of the gaps.

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Well first off I need to know how the algorithm works. I understand its a way to get convex polyhedra to move around accurately and semi-realistically, calculations are dependent on force, torque, directions etc. Most of this flies way over my head, cuz while I understand it all, how exactly to implement this in terms of collision response and stuff I just don't get.

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Here's what the algorithm looks like:

F = m*a

Remebmer that.

So you've done calculus?

Note that:

a = F/m

And that a is the second rate of change of position (which I like to call P). So, what we have here is a differential eqn.

Ultimately, you want to find position. So, rigid body dynamics breaks down to:

A) Figure out F. Write a function that gives F/m.
B) Solve a = F/m for position.

What about angles & such?

In 2d, you have this eqn:

Moments = Moment of Intertia*Second rate of change of angular position

Which is frighteningly similar to b]F[/b] = m*a. It's just a differential eqn too.

What about 3d? Rotation becomes awfully complicated in 3D and everyone seems to do it a different way, play around with it in 2d before you move onward.


Solve the differential eqns with a numerical method, such as Verlet:
http://www.gamedev.net/reference/programming/features/verlet/

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