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manonoc

pb of body freezed after some collisions

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Hi everyone, I've got a pb in my engine: - I resolve a collision using impulse - when the body bounce from a great distance, all is ok - but after some bounces, the body freeze My explication: - the collision resolution have changed the velocities - so the path in the forward direction will change - But the path in the backward direction too, has changed (i use RK4 to integrate the diff equ), but it is not the path that the body has just followed ! - so if a new collision is detected, the bisection method will be applied, and not be able to find a position without collision, to place the body in a position that there is no collision. are you ok with this explication ? is there a way to resolve this ? (contact forces ?) (reminder path ?) thanks

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some precisions about my engine:

when i detect a collision:
- i replace the body to the previous state (x, q, P, L)
- i apply a bisection method to have the precision wanted
- i move the body at a position without collision

(the pb is there, sometimes i can't reach a position without interpenetration from current to previous state)
can it be an precision error ? (an integrator precision error ?)
the bisection begin from 0 (previous state) go midpoint with the current state 0.5, and so on, divide the step by 2 at each pass

- calculate the new P and L, with the impulse method
- integrate

Do you think it's a good procedure ?

what's yours ?

[Edited by - manonoc on March 7, 2008 7:45:25 AM]

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the pb has disappeared after creating an edge_face contact from 2 vertex_face contacts when it's the case...

the point of this contact is the midpoint of the two others (should be the center of mass of the two vertices, but for me, they have the same mass)

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