How to limit how far an object can move in Blender Game Engine? First of all, I have an empty that is constantly being tracked to the cursor. I have a situation where I can select an object with left-click, and upon right-clicking, it is parented to the empty, meaning I can move it by my mouse. When I left-click again, it places it down.

Is there a way I can limit how far it will move while parented to the empty before it stops like it's hit a wall that's a certain distance from its starting point? Also, after I place it down, that "wall" resets to be equidistant from its new position.

What I want (but without the wall):





And then the empty can move further but the model can't.

Is there a way of doing this in logic bricks? I'm sure it's possible in Python but I'm trying to do it all in bricks for this project.
You can make the wall invisible. Then make the cursor object a sensor physics type, and when it collides with the wall, have it send a message to the player to unparent. This method isn't fool proof (if you move the mouse too quickly, then the guy can clip through the wall.) but it's very simple to understand and I'm sure you can make the most of it.