LightTank is a mixed-reality installation that augments a space frame structure with holographic line drawings. Using the anaglyph (red/cyan) stereo projection technique on transparent screens, the haptic-digital construction merges with its surrounding and blurs the boundaries between tactile and virtual. LightTank creates a communal immersive experience with an intimate responsiveness to its audience. The project was conceived by the arc/sec Lab for Digital Spatial Operations at the School of Architecture and Planning at the University of Auckland. Headed by Assoc. Prof. Uwe Rieger, the Lab explores real time Reactive Architecture as a fusion of physical materiality and digital information. LightTank’s interface was developed in collaboration with the Augmented Human Lab at the Bio Engineering Institute. Under the lead of Assoc. Prof. Suranga Nanayakkara, the AHLab focuses on creating enabling human-computer interfaces as natural extensions of our body, mind and behavior.