New Camera Points and Collison point

Can someone help me.Im trying to make points in my game stages like what you would see in the games like Anarche Regins,Rise of Incranets and Dead or alive 5.I want the characters to move freely until close up togther.How do I set up points of collision in the world.And Change the camera to lock and change the view when characters are close togther. Also locking the view but still allowing for 2.5d movement in a 3d space like what you would see in Dead or Alive 5.Where the characters while fighting can interacted with the stage backround and be tossed around.Basicly a mixture of 3-d and 2-d movement.Also a lot of what im trying to do is in game slike Dragon Ball z.Where you can fly around until you get close up.If anyone is willing to help me.I will stay until its done.I will learn how through blue print or C++.How do i talk to these part of the engine??? Please help.Im trying to get this foundation done before i start making move and stages in full.