contacts not recognized when body is changed from circle to rectangle

Question

With help from here I have made a circle body traverse a given path. I have some bodies at some of the path points and have logged contact in didBeginContact. When

Answer 1

It seems like when you change the firstBody to a rectangle (in the didBeginContact method), you don't set the bit mask. From what you described, it appears you want to set it to circleCategory as such:

firstBody.node!.physicsBody?.categoryBitMask = circleCategory

I would put this right below the firstBody.node!.physicsBody?.allowsRotation = false.