A system, method, and computer program for modifying a solid model representation that is manipulated in a computer having software instructions for design, comprising: a computer system, wherein the computer system includes a memory, a processor, a user input device, and a display device; a computer generated geometric model stored in the memory in the memory of the computer system; and wherein the computer system receives user input and accesses at least one data file having a plurality of geometric model definitions that define a geometric model; converts the geometric model definitions into a geometric representation of the geometric model; calculates a plurality of geometric conditions between at least one geometry identified by a user and the geometric model to create a set of constraints; and calculates a modified geometric model with a modified geometry according the set of constraints to display to the user; and appropriate means and computer-readable instructions.