Path: chuka.playstation.co.uk!news
From: colin adams <colin@cobradev.demon.co.uk>
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Collision Detection Algorithms
Date: Tue, 29 Jul 1997 07:47:21 -0700
Organization: Cobra Developments
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Hello All

Here is help with Collision Detection Algorithms, if anyone is
Interested. 
I used some of this stuff in my Demo see-: Hunt Seek Find & Kill PSX
Yaroze 
Demo at-: "http://www.cobradev.demon.co.uk/" (un-ashamed-plug) v.03b Now 
Available (50 hits in a week & no email, strange).

Bounding Cuboid:
For each object, find the maximum and minimum of each the x, y and
z co-ordinates of all the points in each object. If they don't rotate,
this is easy, as it's a constant relative to the centre, if they do, as
in most games, and speed is critical as in game environments, stick
with bounding spheres. Otherwise it's just comparing these values to see
if there's an intersection. It _is_ useful for environments which don't
change. Look at "http://www.cs.unc.edu/~hoff/vfculler/viewcull.html"
It's not collision, but it covers bounding boxes pretty well.

Bounding Sphere:
 if ((a.x-b.x)^2+(a.y-b.y)^2+(a.z-b.z)^2 < a.radius^2+b.radius^2 ) 
     objects A and B in collision;

Calculating the Radius of the Objects:
Pick a centre point. You can just average all the points in the object,
though the centre of mass may be more convenient for physics modelling.
Anyway, pick a centre point. Find square of the distance from each point
to the centre: (p.x-c.x)^2+(p.y-c.y)^2+(p.z-c.z)^2, the largest one is
the square of your radius. I managed to pre-calculate this successfully
via
*.Dxf format, as this format is adequately documented. but I would like
to 
pre-calculate this via *.TMD during the Project initialisation. Can
anyone 
help out?  

BTW if anyone is going to ECTS see-:"http://www.ects.com" for the Latest
Information. Keep the Faith.

--
Cobra