1. An apparatus for coordinating building design comprising: a data memory for storing a three dimensional building model, the three dimensional building model having a plurality of elements, each element having a plurality of attributes; an element ownership processor for assigning ownership of each of the plurality of elements to one of a plurality of users, wherein each of the plurality of users has ownership of a subset of the plurality of elements; a model modification processor for receiving the three dimensional building model and for allowing a user to modify only elements that they have ownership of; and a model synchronization processor for receiving only modified elements from the model modification processor and updating the three dimensional building model to include the modified elements.