simultanous collisons and rigid body stacking

[2chrisp]

hi,

im on my way on implementing a simple physics engine for 3D boxes, without rotation, thats all i need for my project. i have implemented runge kutta integration, aabb sweep collision detection, and collision response that depends on the restitution of the boxes. there is air drag, gravity and wind that influences those boxes. right now, i calculate the new postitions with every new step, then i check only for one collision, calculate the hit time, interpolate linearly the hitposition during my step time, move the box from the last step postion to the hit position, apply the hit impuls, and move it to the position where it should be at the end of the step time.
is that in general the correct way to handle collisions? or should i just calculate the hit impuls, leave the box penetrating the other box and let the boxe move out of collision with the next step?

how should i handle simultanous collisions? its my goal to have the boxes rest obove each others. again, there are no rotations, i know this will look strange sometimes when a box rests on the edge of another box and does not slide over it.
should i calculate all the hit impulses of all the collisions a box has and the result is the sum of all the impulses?

any help appreciated, especially papers and tutorials that are not way over my knowledge. i already tried to look into the box2d source but didn't find my way through. a general description of the steps for collision handling and stacking would help a lot, i'm a little confused by all the papers i have read.

thanks
chris

[hiroshi]

This document can be very helpful:

http://www.digitalrune.com/Portals/0/KB ... namics.pdf