Funes and Pollack [43] performed one of the earliest
attempts to physically instantiate evolved 3-D designs by placing
physical LEGO bricks according to the schematics of the
evolved individuals. A direct encoding of the physical locations
of the bricks was used and the fitness was scored using a
simulator which predicted the stability of the composed structures.
Additionally, Hornby and Pollack [44] used L-systems
to evolve furniture designs, which were then manufactured
by a 3-D printer. They found the generative encoding of Lsystems
produced designs faster and with higher fitness than a
nongenerative system. Generative systems are known to produce
more compact encodings of solutions and thereby greater
scalability than direct approaches [45].