how does the object get pushed through the wall? maybe you wrongly build up extreme forces (for example by setting the velocity each frame)?
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did you get NewtonAddBodyImpulse() working now?
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btw. i think the new newton version isn't that far away anymore. it will be great. it will be much faster (stacking hundreds of bodies won't be a problem anymore) and there will be new stuff like an easier to use vehicle joint and character controller.
