The present invention is directed to an object construction device configured to enclose a specified assembly area and assemble objects, such as toys, using standardized interlocking assembly units. The construction device includes processor with a memory device configured to access an instruction set encoding the assembly instructions of the object. The processor executes the instruction set in order to control and direct an assembly unit manipulator to additively construct or assemble the object from the interlocking assembly units. The assembly units are configured with surface features that interconnect the assembly units such that once connected they are substantially permanently attached to one another.