Building on previous projects created by Neri Oxman and her team, in collaboration with Stratasys—including Imaginary Beings (2012) and Wanderers (2014)—Rottlace is similarly printed as a single, multi-functional material system, composed of rigid materials combined with nano-enhanced, elastomeric structures. The intricate fibrous tissue is made of soft and flexible materials designed to accommodate facial movement. The materials’ durometer varies as a function of the structural type they are intended to provide. Continuous property transitions—ranging from stiff bone-like structures to semi-flexible ligament-like structures, to flexible fiber-based connective tissue structures—are computationally generated and digitally fabricated. Specifically, the fibrous tissue is computationally generated as modified principal curvature directions of Björk’s facial scan—obtained as point cloud data—while the bony-like tissue emerges as support structure at points of high divergence from the principal curvature field. While bone-like locations are geometrically informed, their material composition is continuously graded—from stiff to flexible, and from opaque to transparent—as a function of geodesic distances given by the face-scan. Graded and tunable material properties are achieved through custom software as well as heterogeneous material modelling workflows. Combined, this computational framework enables micron scale control of 3D printable material placement over highly complex geometric domains. This enables the design and 3D printing of complex, large-scale objects with continuous variations of modulus and transparency, within a single build. Properties, such as structure to material composition, of each mask include a number of length-scales, informing their mechanical properties and behavior: (1) on the centimeter scale, the 3D printed musculoskeleton is designed to allow for flexible movement, while providing integrity to, and support of, its overall form; (2) on the millimeter scale, the fusing and parting of fibers with varying material compositions enables the overall structure to be self-supporting; and (3) on the micron scale, material droplets are placed, diffused, and spatially aggregated to provide continuous material variation within a single ‘muscle-skin’ object.