A system and method for building three dimensional objects may adjust data used to build the objects to, for example, improve quality or correct for defects. A printer may, for example, accept data representing the object and modify the data according to an adjustment parameter; the printer may build the object according to the parameter. The parameter may be, for example, calculating an adjustment parameter in an X-Y slice plane to compensate for inaccuracies caused by diffusion of materials into one another.