An isometric world is the easiest type of 3D world to create in Flash.
There is no perspective change in an isometric world.
One of the best features of an isometric world is that you can reuse graphical assets at any place in the world, as is, because there is no perspective change.
An isometric system is created by rotating a system that is currently aligned with the Flash system by 30° around the x-axis and then by 45° around the new y-axis.
Because of the useful (and fast) depth-calculation equation we use, we are able to restrict positioning to the x, -y, -z octant.
Making an isometric system using tiles (that is, a tile-based world) is the most efficient and best way to create an isometric world. It makes collision detection and z-sorting much easier.