1. A method for resolving collisions for placement of objects in a three dimensional model, the method comprising: attributing a first state to each object having a hard geometry and a second state to each object having a soft geometry; predefining a first set of rules based on regulatory requirements to determine whether multiple objects may occupy the same spatial volume based on the combination of the object states, the first set of rules covering all permutations of the first state and the second state and including the following rules: two hard geometries cannot occupy the same space; a hard geometry and a soft geometry cannot occupy the same space; and two soft geometries can occupy the same space; placing a first object in the three dimensional model; placing a second object in the three dimensional model; checking for collision of the first object with the second object in the three dimensional model; and resolving the collision based on the first predefined set of rules.