As a part of a exam project a pal and me are working on a particle system consisting of balls. The system is implemented in C++ and is based on classes. We have a base class, and a 2 derieved classes: a ball and a terrain. The terrain is a xy, height map. There is only one instance of this map. The ball has the following variables. 3d-vector: position speed sum_of_forces The base class has a function called interact, wich allows each element to ask all the other elements in turn, what force exist between them. (caused by gravity, collisions etc) The idea is to generate a global loop wich in turn lets each ball sum up the forces from the other objects in the system. When all the balls has summed up their forces. The sum_of_forces can be used to update the speed and the position of the balls. The problem occurs when collisions between balls and terrain is detected. If a colliding ball asks the terrain wich force the terrain will generate, we cannot decide the size of the resulting force. We think it perhaps is impossible, because the force needs total force acting on the ball to find the normal force generated from the terrain. We would very much like comments/suggestions to the problem.

Folks,

This is a homework/schoolwork problem, please do NOT provide solutions to the problem! The question is related to game development, so I''ll let the thread remain open, but ONLY if you provide the poster with suggestions and not solutions or implementations!

Forum FAQ

Graham Rhodes
Senior Scientist
Applied Research Associates, Inc.

http://www.cs.unc.edu/~ehmann/RigidTutorial/
http://www.gamasutra.com/resource_guide/20030121/kennedy_01.shtml
http://citeseer.nj.nec.com/cache/papers/cs/1312/http:zSzzSzwww.cs.unc.eduzSz~dmzSzUNCzSzPHYSICSzSzPaperszSzimpulse.pdf/mirtich95impulsebased.pdf
http://citeseer.nj.nec.com/cache/papers/cs/1312/http:zSzzSzwww.cs.unc.eduzSz~dmzSzUNCzSzPHYSICSzSzPaperszSzbaraff94.pdf/baraff94fast.pdf

for contact forces. You do need the normal at the point of contact.

Those should get you a A+ for your assignment. If you understand what it''s all about

quote:

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Original post by oliii
http://www.cs.unc.edu/~ehmann/RigidTutorial/
http://www.gamasutra.com/resource_guide/20030121/kennedy_01.shtml
http://citeseer.nj.nec.com/cache/papers/cs/1312/http:zSzzSzwww.cs.unc.eduzSz~dmzSzUNCzSzPHYSICSzSzPaperszSzimpulse.pdf/mirtich95impulsebased.pdf
http://citeseer.nj.nec.com/cache/papers/cs/1312/http:zSzzSzwww.cs.unc.eduzSz~dmzSzUNCzSzPHYSICSzSzPaperszSzbaraff94.pdf/baraff94fast.pdf

for contact forces. You do need the normal at the point of contact.

Those should get you a A+ for your assignment. If you understand what it''s all about

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lol... just 3 years late. -PmanC

Actually, it was just posted today, but grhodes_at_work registered on 5/31/00, which is most likely the cause of the confusion.