Doomig arround

Hello,
I’m new in java game programming, I usually program in VB and in Developer forms so be patient with me please.
The application I NeedI have to program a game in which the user has to walk around a house turning on/off appliances like TV, radio, computer, etc. (This is the difficult part for me)
While this happens the game should calculate and show the total energy that is consumed in the house. (This is the easy part)
What I have learned
Well I’m looking for some advices. What I wish to do is a DOOM like game. Working with the OBJ Loader demo of Java3d I’ve noticed that I can build my objects in 3ds MAX, export them to OBJ and use them in J3d , that’s great!. I did not try to make a bitmap textured object yet, I wish not to find problems with this.
The help that I need
1). I have got to navigate using mouse and keyboard too, I suppose there is a library for joystick over there, but I have not Idea how to restrict the navigation, I mean that I don’t want my user to cross through walls and I don’t want him to fly at least not too high from floor. How should I restrict navigation?
2). The second functionality that I have no Idea how to implement is a sight, I mean a 2d circle in the middle of the user screen that will be used to point an appliance and turn it on or off. Is there a way to know when an object intersects with the sight?

  1. My last question is something that I know most of you have already done. I have to show all time the position of my user in the house, using a 2d plane of it. Can you help me to do this?

If there is a demo that could help me to build this application please tell me where to find it.

Thanks on advance
Igor