Box2d forces and speed after collisions

Question

I just wondered if I can keep the velocity of my bodies unaltered after a collision. I have some ball randomly spawned with a force applied to their center, there is no gravity and every element has zero as friction and one as restitution but still someone speed up and someone else slow down after a clash. How could I manage to keep my speed constant?

Answer 1

Make the fixtures which you use to construct the bodies isSensor to true like:

//At the definition of the Fixture
 fixtureDef.isSensor = true;

This will still generate the collision response but the bodies won't b affected when they collide