MathEngine

Are you better off coding your own physics?

IMHO the answer to this question really depends on how far you want to go with it.

If your game world is not too complex...and you don''t need the objects to be too complex in shape (say just cubes, and spheres etc), and you don''t need things like linked objects, or to be able to stack objects on top of one another...then my advice would be to have a go yourself...it''s much more rewarding.

However....the sort of code you''ll find on the net by the likes of Chris Hecker, really is the very, very tip of the Iceberg. If you want really serious physics in your game, then unless you have a math degree and/or lots of time to read books, you''re gunna run into problems.

For serious physics, you''ll need a ''constraint solver'', and writing one of these is not to be taken lightly. The constraint solver calculates all the forces acting on the bodies in your system, and without it you won''t be able to get objects to interact with one another very realistically. Again, if you don''t need it to be too realistic, then there are ways of faking the force calculations without a constraint solver, but that''s only going to work in very simplistic situations, so it depends on what you need to model.

We use MathEngine for our game for the simple reason that to produce the results that we get from MathEngine, ourselves, would take months (or even years) of work, and we''d rather spend that effort on the game itself. (If your interested in seeing what were doing, then have a look on our website... http://www.vividimage.co.uk).

Hope that''s of some help,

Will

Vivid Image
www.vividimage.co.uk

the objects to collide are simple bounding boxes (of 8 vertices) and the world is also divided so that at any one time, an object would be contained in a box (four walls).

i need to take care of object-world collision, and object-object collision, but no spheres are involved (all planes).

Since this is my first full-scale game, i don''t need anything too advanced, but the demos that i''ve seen with math engine are fairly impressive. but 1.1 does not have plane-plane collision, only sphere collision in one form or another.

how long did it take you guys to learn, use, and implement math engine?

a2k

Well, first off we''re using the new Version 2 SDK, which is a bit tricky to get hold of at the moment...you''ll have to ask MathEngine very nicely. But the good news is that it''s much, much, much better than the previous version. It''s extreemly fast, and has alot more features, so it''s well worth waiting for.

I''ve found it very easy to use, and it only took us a few weeks to get things working initially. One really nice thing about it is that it has two layers...a bit like the Direct3D Retained and Immediate modes...so you can either do high level stuff, or you can dive into the guts and use the low-level immediate mode for extra speed.

Even if you can''t get this new version quite yet, then you should be able to do what you need to do with v1.1. From what you describe, you should just need to have Box to Box and Box to Plane collisions, which I''m pretty sure it does ok. If you have problems with planes, then you can always make the walls out of boxes instead, so then you can just use box to box collisions for everything.

Anyway, hope that''s of some help. Shout if you''d like more info.

Will
Vivid Image