Retrofitting Existing 3D Objects with Surface-Conforming Capacitive Sensing

2026-07-18

AI Summary

This work addresses the challenge of integrating capacitive multi-touch sensing onto complex curved surfaces without altering their internal structure. The authors propose a generative computational fabrication pipeline that begins with 3D scanning to capture an object’s geometry, followed by automated generation and optimization of electrode layouts tailored for mutual capacitance sensing. Under physical and hardware constraints, these layouts are flattened into 2D templates and precisely transferred onto the target surface using dynamic projection-based registration to guide conductive material deposition. This approach enables, for the first time, the deployment of high-conformality, customizable mutual capacitance sensor arrays on arbitrarily complex surfaces without modifying internal cavities. The method’s efficacy and practicality are demonstrated through real-time multi-touch systems successfully implemented on four distinct non-planar objects.

Abstract

Augmenting the surface of 3D objects with capacitive sensing is challenging when their volumes cannot be modified. In this paper, we present a generative computational fabrication pipeline that retrofits surface-only sensor layouts to 3D geometries for multi-touch interaction. Our method scans a real-world object to obtain its 3D mesh, generates and optimizes a 3D sensor design of drive and sense lines for mutual-capacitance sensing under physical and hardware constraints, and unfolds the design into individual 2D stencils that can be cut from conductive material. Our fabrication pipeline cuts these stencils from thin copper foil with a vinyl cutter and then assists manual sensor attachment by projecting the sensor design onto the dynamically registered real-world object. We connect the resulting electrode mesh to a mutual-capacitance scanning controller and resolve touch interaction in real time. We demonstrate our approach with four 3D geometries and evaluate our method and fabrication pipeline on them.

Problem

• capacitive sensing
• 3D objects
• surface retrofitting
• multi-touch interaction
• computational fabrication

Innovation

• surface-conforming sensing
• computational fabrication
• mutual-capacitance sensing
• 3D object retrofitting
• generative design