1. A three-dimensional CAD model creating apparatus comprising: a processor executing program modules for: creating, by a table creating program module, tabular data that describes change logic for each changed state, the change logic associating a changed state with a logic condition to be satisfied to shift to the changed state, the change logic including a conditional branch, the changed state being a shape and a structure of the three-dimensional CAD model after transformation of the three-dimensional CAD model; converting, by a data converting program module, each change logic set in the created tabular data into a description in a certain program language, and creating a model built-in program that includes each description in the certain program language; registering, by a model built-in program IO program module, the created model built-in program to the three-dimensional CAD model; and transforming, by a three-dimensional CAD software program module, the three-dimensional CAD model when receiving an operation for transforming the three-dimensional CAD model, based on the operation and change logic described in the registered model built-in program; and a memory for storing the model built-in program.