Resumen: Two recently completed high-rise residential developments, located side-by-side in a neighbourhood in Singapore, are compared in a post-occupancy study. Both have near identical demographics, are exposed to the same microclimate, and constructed with a similar palette of materials. The primary difference is form. One has a high degree of porosity with inner voids that act as conduits for natural air flow and offer a sheltered space for social engagement. The other is more compact, less porous and has social spaces attached to the building¿s exterior. The study included surveys of residents, behavioural observations and environmental measurements. On three counts ¿ self-reported energy use, thermal comfort and social interaction ¿ the former appears to be more successful than the latter. Findings suggest that building form affects multiple outcomes at once. A form strategy that lowers energy use, for instance, can also improve social engagement. The implication of this socioenvironmental approach to form-making is discussed in the context of high-density tropical typologies.