Imagine a boat floating in a rough sea. The sea is a soft-body nurbs plane. The boat is always touching, penetrating and colliding with the sea. My idea was to parent some dummy objects to the boat hull and emit splashes from them when they hit the sea surface. If you use normal collision system, the dummies will not be able to go through the sea surface (according to my tests... i might have done something wrong though). Anyway, this is why I only want to know where and when the dummy has touched the surface and let it go through the surface freely...