01 / The Question
AC|D 4 investigates the invisible trace left by a temporary spatial experience.
Most installations are judged while they stand. This one is judged by what happens afterwards — by what a visitor carries out through the exit and still holds days later.
The research examines four conditions. Memory: how an experience settles into a person. Perception: how little a space needs to offer before the mind completes it. Participation: what changes when a visitor stops observing and becomes part of the material. Ephemerality: what a place can mean once it accepts that it will end.
02 / The Thesis
The Cube is not conceived as an object to be admired from outside. It is completed by the visitor. The physical installation is temporary; the project is judged by what persists after the encounter.
In neuroscience, an engram is the physical trace left in the brain by an experience, making memory possible.
The project does not attempt to design a memory directly. It designs the conditions from which memory may emerge. The scientific concept is used as a conceptual framework, not as a claim of proof.
03 / The Object
04 / The Fenda
One thin vertical luminous line. Uninterrupted. Full height.
Visually continuous — the architectural translation of the “|” in AC|D.
It is not segmented. It is not a portal. It does not open.
The fenda signals the threshold.
The physical entrance remains concealed.
05 / Five Days Sealed
5.
06 / The Experience
The Cube appears as an interruption in the city.
The visitor remains outside long enough for expectation to become attention.
The fenda signals the threshold. The physical entrance remains concealed.
North opening, 1000 × 2000 mm, recessed in the dark base.
Inside, the visitor becomes part of the work.
Saturated red light · low-frequency sound · controlled darkness · stillness.
The Cube releases the visitor without explaining the experience.
South opening: exit and emergency egress.
The experience reappears later as memory.
07 / Seven Minutes
7′
Maximum capacity is up to two people per cycle. The experience lasts seven minutes — long enough for expectation to dissolve, short enough that nothing is explained.
08 / The Red Field
The interior is not a room. It is a condition.
Four walls and the ceiling carry one continuous field of red light. The floor stays dark. Nothing is displayed; the room itself is the image, and the visitors are the only figures in it.
09 / The Evidence
10 / The Visitor Cube
Before entering, the visitor chooses between a recording-consent cube and a non-recording cube. The cubes are made from aluminium offcuts generated by the AC|D 4 material system; the chosen cube leaves with the visitor. When two visitors enter together, recording requires consent from both participants. If either participant declines, the entire seven-minute cycle proceeds without recording.
The recording-consent cube contains an on-metal NFC tag — selected specifically to function on an aluminium substrate — and a QR code that provide access to the visitor's private video of the passage. Tap with a compatible phone or scan the code. No account. No facial recognition. The video remains available for twenty-four hours, then disappears.
The non-recording cube remains a physical residue of the experience but does not provide access to a recorded video. Either cube is at once a consent instrument and a material memory device.
11 / Technology
Every system exists only to hold the experience steady. None of it performs. No AI system forms part of the approved project.
12 / Memory by Subtraction
Four concepts frame the research. They are used as an interpretative model and as research references — never as claims of measured effect.
A memory connected to a personally lived event.
The physical trace that supports memory.
The visual impression that survives after the stimulus.
The effect that persists after the original field has disappeared.
13 / Technical System
The Technical Dossier is issued for design and tender, not for construction. Technical specifications represent the current stage of design development and remain subject to specialist validation before construction.
14 / Circularity
The Cube is designed for disassembly: modular assembly, reversible connections, separation of structure and content, replaceable activation layers, reuse and repair rather than replacement. Its circular performance has not yet been empirically verified.
The visitor cubes are already part of this logic — made from aluminium offcuts generated by the material system itself.
At the end of the installation lifecycle, material from the Cube may be recast, numbered and preserved as a relic. The number of relics and their destination depend on the site, the activation and the commissioning model.
15 / Master's Thesis
AC|D 4 is Ana Costa Martins' Final Major Project in the Master in Interior Design at the Cascais School of Arts and Design, academic year 2025/26. The project is currently unbuilt.
How can an ephemeral spatial object install lasting memory by subtraction — through tension, mystery and light — instead of pursuing it through the accumulation of stimulus, and do so under a circular logic?
Practice-based research; research through design. Knowledge is produced through the act of designing, with memory by subtraction as the coherence criterion for every decision. A future empirical evaluation is proposed — the Awe Experience Scale (AWE-S), delayed recall, and peak-end comparison. No empirical results are currently claimed.
Frayling · Böhme · Debord · Kahneman et al. · Keltner & Haidt · McDonough & Braungart · Pine & Gilmore · Rudd et al. · Yaden et al. · Young · Zumthor. Full citations follow the thesis reference list.
Future commercial application — speculative
16 / Future Activations
After the academic phase, AC|D 4 is intended to evolve into a modular platform for immersive temporary activations. The external object remains recognisable while light, sound, image, scent, content, interaction and relic may change with each activation concept. Every activation begins with one defining idea — none is interchangeable.
Concept scenario · fragrance
The red field gives way to a scent held in darkness. Changed layers: light, scent, sound. Retained: the monolith, the fenda, the seven minutes, the consent cube. Possible relic to be developed according to the activation concept. Reuse: activation layers replaced; structure untouched.
Speculative activation · music
One unreleased piece, heard once, by up to two people at a time. Changed layers: sound, light tempo. Retained: the object, the ritual, the 24-hour private video. Possible relic to be developed according to the activation concept. Reuse: same platform, new content.
17 / What Comes Next
The object disappears.
The memory remains.
You will know
when you feel it again.
