One way collision reaction in FP3

Topics: Developer Forum, User Forum
Oct 14, 2010 at 6:11 PM

I'm trying to convert some of my work from Baby Maker Extreme from FP2 to FP3 along with some other changes. I've gotten a lot into the new physics engine, but there's one feature in particular that I can see is making trouble. One of the "odder" interactions in Baby Maker was how collisions worked. When two objects that I WANTED to collide hit each other (Baby + doctor) I had set it up so that the doctor would get "hit" by that initial physical interaction and fall down, while the baby would actually keep its momentum. The baby could spin, but it would not slow down as a result of the collision. I was able to do this using a small hack by forcing the baby's speed immediately after the collision, and ignoring all future collisions between the two bodies (baby and doctor would only consider each other collidable for that first frame of collision).

Now, here's the problem. In FP3 there seems to be a concept of a continual collision, so if object A is continually colliding with object B, that only activates the collision handler once, but will still physically PUSH object B from frame to frame, until they are separated enough that their collision lists are reset. So, even if I say that those objects should not collide with each other any more after that first hit, they won't pay attention to that request until after they are separated. I want the baby to pass right through the doctor it just hit. It shouldn't be pushed back by the doctor, nor should it effect the doctor's motion for more than that initial impact. So, is there any way to force this behavior, or to clear the "memory" of these two objects so that they don't remember that they were intertwined in the previous frame? Thanks for any insight that can be provided!