Background

Traditional pressure sensors are typically either rigid or membrane-type, which limits both product form and design freedom, while also reducing comfort in interaction. In most existing solutions, the product’s appearance and the sensing function are treated separately, meaning designers often rely on ready-made sensors inserted into an object after the fact. Invisible addresses this issue with a more integrated approach: by coordinating parametric structure and conductive regions, pressure sensing becomes part of the product’s structure rather than an added component.

Mechanism

Invisible uses a sandwich-style capacitive pressure-sensing structure. Inside the system, upper and lower conductive regions are separated by a non-conductive parametric lattice. When force is applied, the lattice deforms, changing the distance between the conductive layers and therefore changing the capacitance. By sampling the relationship between pressure and capacitance, we translate structural deformation into a measurable sensing signal. In this way, the structure is not only a support and cushioning medium, but also the sensor itself.

Design and Fabrication

To make this sensing structure adaptable to different products, we developed a Grasshopper-based generation program. Starting from selected target surfaces, the system builds a lattice mapping grid and automatically distributes conductive and non-conductive lattice regions. Through a simple interactive panel, users can quickly adjust the size, position, and number of sensing areas, enabling flexible pressure-sensing structures to be customized for irregular forms within minutes. The workflow is directly connected to digital fabrication and supports rapid iteration and personalization.

Invisible is fabricated through multi-material integrated 3D printing, combining conductive material and non-conductive flexible structure within a single production process. Compared with conventional approaches that assemble separate parts and standalone sensors, this workflow reduces extra assembly and creates a tighter integration between structure, function, and appearance. Because the geometry is generated parametrically, the system can be applied not only to standard forms but also to more complex and personalized surfaces.

Concept

Invisible is a parametric capacitive flexible pressure sensor crafted through a 3D printing process that combines conductive and non-conductive materials. This sensor seamlessly integrates into the parametric structure and overall product design, offering a perfect blend of customization and integration. This user-friendly approach caters to the convenience of designers and developers.

The key value of the project lies in three aspects. First, it supports rapid customization and generation, allowing sensing structures to be quickly adapted to different surfaces and interaction requirements. Second, it aligns well with digital fabrication and enables fast processing and production through multi-material printing. Most importantly, it establishes an interaction between material and parametric structure, making pressure sensing an integrated outcome of structure and function rather than an added module.

Application

Gait Pressure Detection Sports Shoes

In the sports shoe application, we use the flexible parametric pressure-sensing structure directly as part of the sole. This allows the sole to remain soft, breathable, and customized to the foot while also sensing pressure changes in real time. By distributing multiple sensing points, the system captures pressure-capacitance signals from the foot and maps them into a dynamically deforming virtual model that visualizes gait changes.

This unique fusion not only aids athletes in analyzing foot pressure but also empowers individuals with lower limb disabilities to gain insights into their foot pressure. The virtual shoe model also facilitates personalized shoe design based on individual foot shapes.

Adaptive Human Posture Chair

In the chair application, we combine the parametric flexible pressure sensor with inflation and deflation control, allowing the chair to actively adapt its support to the user’s posture. After a person sits down, the system reads a stable capacitance-based pressure signal, identifies regions with relatively lower pressure or insufficient support, and inflates corresponding airbags to compensate for seat and lumbar support. After maintaining the new state for a period of time, the system can begin another round of adjustment. This application shows how Invisible moves from sensing to adaptive feedback, turning furniture from a passive object into one that actively responds to the human body.

Value

Invisible is not only a new flexible pressure-sensing structure, but also a design approach that brings sensing, structure, and form generation into the same parametric system. In this framework, pressure sensing no longer depends on externally attached rigid sensors, but can be naturally embedded into wearables, furniture, and other interactive objects, creating a more integrated relationship between structure, function, and user experience. With its flexible, integrated, and customizable nature, Invisible opens new possibilities in product design that combine comfort, adaptability, and innovation, while laying the foundation for more natural, intuitive, and intelligent interactions. More importantly, the sensing system is highly extensible: in human-computer interaction, it can support more continuous and expressive forms of input; in smart wearables, it can enable more personalized, health-oriented experiences; and in healthcare scenarios such as pressure ulcer monitoring, it has the potential to provide more accurate, real-time, and accessible sensing and diagnostic support. Invisible therefore represents not only a specific technology, but also a scalable design strategy for future complex interactive applications.

Exhibition & Publication