Hey everyone, I have always been a good programmer but have recently had a strong urge to begin game development. I am currently in school for aerospace engineering and one of the classes I am having to take is dynamics. Well, it''s more complicated than I had expected and our whole class is struggling. I guess this question is geared toward the programmers, I am just wondering, when programming the physics of the worlds, do you ever use polar or tangential/normal coordinates? Is it as complicated as most dynamics problems or mainly physics 1? I just need an idea so that I can prepare myself. Thanks guys! Koolboarder007

I''d probably guess that 95% of the time plain XYZ coordinates are what you use.

However, those other coordinate systems don''t exist purely because some guy thought it would be fun to confuse schoolchildren... they do indeed have their uses.

I can''t think of any offhand, though.

Superpig
- saving pigs from untimely fates, and when he''s not doing that, runs The Binary Refinery.

To use polar (or normal/tangential) coordinates you need a center. If the movement of your objects is not done around a center, then polar coordinates will get in the way, instead of helping. Polar (or other special systems) are only useful in a handful, very limited situations (pendulum, wheels, etc...). Physics in a game level made of hundreds of objects all moving differently is too much for polar! However, when polar coordinates CAN be used, they are SO powerful that you''ll just want to throw away your cartesian coordinates.

The problem with physics engines is not the math. A computer can compute almost anything. The hard part is to find a good way to simulate physics accurately, and to teach your engine to solve any problem, just like you do.

Superpig :
- ellipses, hyperboles, paraboles are a hell to work with if you stick to XYZ.
- Speed and acceleration computation in XYZ are a hell to determine when studying a circular motion.
- Central forces (gravity, for instance) are much better handled with polar.
- Anyhing circular is better done in polar.

ToohrVyk
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