System and method for selection of a print head of a three-dimensional printer

A method of selecting a printing head of a three-dimensional (3D) printer, the method comprising:

• a. receiving a 3D model comprising a first 3D shell and one or more second 3D shells, wherein each of said 3D shells comprises coordinates of a plurality of shell points that describe a 3D polygonal water-tight mesh, and wherein said first 3D shell and said one or more second 3D shells share an overlapping volumetric region;
• b. receiving a priority list attributing a priority value to said first 3D shell and said one or more second 3D shells;
• c. producing an ordered set of slices of said 3D model, each slice comprising a plurality of slice points defined by X, Y, Z coordinates;
• d. for at least one slice, determining an overlapping region in which one or more slice points belong to the first 3D shell and to said at least one or more second 3D shells wherein the first 3D shell is associated with a first property vector value, and wherein at least one of the one or more second 3D shells is associated with a second property vector value;
• e. attributing a target property vector value to said one or more slice points in the overlapping region based on said received priority list and also based on a received overlap rule wherein the overlap rule comprises at least one condition for the first property vector value and the second property vector value;
• f. selecting a printing head based on the attributed target property vector value;
• and
• g. dispensing a printing material from said selected printing head.