Patent ID: 7700016

Claim:
A method of fabricating a three-dimensional model on a layer-by-layer basis, the three-dimensional model having at least one void region, the method comprising, at each layer of the three-dimensional model, the steps of: in successive layers of the three-dimensional model, (a) forming a mold with a sacrificial mold material, including in each layer having the at least one void region, depositing lines of the sacrificial mold material in a grid pattern delineating a region of the layer included in the at least one void region, whereby grid patterns in successive layers of the at least one void region form partitions of the sacrificial mold material defining filler spaces for receiving a model material to form filler elements of the model material separated by the sacrificial mold material partitions occupying the at least one void region so that, concurrently with fabrication of the three-dimensional model, the at least one void region is filled with a plurality of the filler elements which are formed of the model material and enclosed by the sacrificial mold material partitions; (b) filling the mold with the model material deposited at a rate faster than a rate at which the sacrificial mold material is deposited; (c) removing a desired thickness of the sacrificial mold material and the model material to reduce a fabricated layer to a selected thickness of the sacrificial mold material; (d) repeating steps (a) through (c) until a composite model is completed, and (e) removing the sacrificial mold material by a process affecting only the sacrificial mold material, including, removing the sacrificial mold material from the composite model to release the filler elements from the composite model thereby to form the at least one void in the three-dimensional model.