this just keeps getting more and more fun ;/ i just finished reading (read: desperately trying to understand a single equation/word) Baraff''s rigid2.pdf paper (http://www-2.cs.cmu.edu/afs/cs/user/baraff/www/pbm/rigid2.pdf). oh my word this is one hell of a subject to start on i understand all the force acting on a body stuff now, thats ok, im actually in the process of writing code that does it. i also understand how to deal with multiple collisions, although i havent written that code yet.

what i am totally bamboozled on is this resting contact stuff! quadratic coding and whatnot - i dont even know what that is :s i dont think i will ever implement such a system, as it looks waaaaaaaaaaay too complicated for my liking. but i was wondering if there is a way around it, a way to approximate resting contact without having to mess about with all that nastiness?

at the moment im thinking for each contact point, if the relative velocity of the objects is zero i could just ''stick'' them together as it were, and as soon as the relative velocity becomes greater than zero treat them as independant objects again. likewise if the relative velocity is less than 0 i could just push the objects back out of each other a bit. any thoughts on this?

going back to what i previousley posted about the book - thats all about frictional contacts isnt it - which, after reading Baraff''s second paper (link above) appears to be just as complex :/ i think i may have to fudge that area too as it really is way over my head, im so dumb :D

i guess its now a case of not understanding or implementing this rbd system, but more a case of fudging the areas i can never hope to code correctly, namely the resting contact and frictional contact areas. does anyone know of how i might go about fudging this, or know of anyone who has done a similar sort of thing and resorted to simpler solutions?

thanks for your support and time everyone who has replied to this thread with your input and links i feel i have learnt something worthwhile

"We are what we repeatedly do. Excellence, then, is not an act, but a habit." - Aristotle

Multiple resting contacts are the most difficult part of the simulation. The "quadratic coding and whatnot" is not the easiest way to do it.

If you go to:
http://www-2.cs.cmu.edu/~baraff/papers/

You want to read this one:
http://www-2.cs.cmu.edu/~baraff/papers/sig94.pdf

I have read a lot of papers about this subject, and this seems to be the most practical method to handle multiple contacts with friction.