This research developed a computation method that synergies the Geometrically Informed Non-Planar toolpath (GINP-toolpath) and Geometrically Informed Variable Material Deposition (GIV-Material Deposition) to produce ultra-lightweight topology optimized building elements. Additionally, several toolpath strategies, including lead-in and lead-out strategies, were developed for 3D printing a multi-branched concrete structure. A 1:1 scale load-bearing wall measuring 1.2 meters wide and 2 meters height was successfully designed and fabricated through the development of a robotic non-planar 3DCP process utilizing a one-component (1k) end-effector alongside. This method allowed the fabrication of a materially and structurally optimized complex form, the Branch Wall, with improved overall structural performance and over 68% material reduction in comparison to traditional wood formwork casting, as well as genral 3DCP practice. The true potential of 3D Concrete Printing (3DCP) lies in the strategic placement of material only where it is needed, enabling material reduction and waste-free fabrication. However, real-world practice in 3DCP often involves excessive concrete consumption and little attention to material optimization. A handful of emerging research has focused on coupling 3DCP with topology optimization

(TO), which is a method for material reduction that inherently produces geometrically complex features such as cantilevering branches. These research avoids the challenges associated with direct 3DCP of geometrically complex form by discretizing an element into small non-complex components, which are then post-assembly.