demo 1 and visualizer
Motion Morph: Automated Mechanism Creation for Accessible Object Adaptation
Sanjana Satagopan, Jerry Cao, Jennifer Mankoff, Shwetak Patel
Abstract
Everyday objects have fixed motion inputs that are difficult to adapt on a case-by-case basis without engineering expertise. For example, turning a jar lid or opening a door requires grip strength that many individuals with limited hand mobility cannot perform. Through MotionMorph, we introduce an automated approach to generate 3D-printable mechanism adapters that convert an object's existing motion into a desired output motion, with applications in accessibility.
Limitations of Existing Approaches
Current tools often require engineering expertise:
From Motion to Mechanism
Mechanism library
We modeled three of the most common joint types for motion translation, adapted from Roman's mechanism taxonomy: gear and rack, spur gears, and bevel gears. Each joint is parameterized by the object's physical dimensions, ensuring the generated geometry fits the specific object rather than using generic sizing.
Opening a Jar Lid By Pulling Upward
Making the Optimal Chain
We use a simulated annealing approach by beginning with an initial random sequence of mechanisms and iteratively tweaking the chain to find the optimal system.
Start with a Random Chain
Simulate Full Motion
Score Against Target
Tweak Chain (swap, add, remove)
Visualizer
We designed an interactive 3D visualizer displays the mechanism assembly alongside motion indicators showing the input and output axes.
Digital Twins
As part of the process, we discovered how we can recreate a digital copy of the real world, building off previous research pipelines such as CARTO [5].
Future Work
Future work includes enabling users to specify a target output path as a spatial curve rather than a single axis. Additional directions include automatic motion axis detection from object scans, attachment geometry generation to integrate adapters directly onto objects, and extending the mechanism library.
Opening a Jar by Pushing
Closed
Open
References
[1] Chen et al. Reprise: A Design Tool for Specifying, Generating, and Customizing 3D Printable Adaptations on Everyday Objects. UIST 2016.
[2] Li et al. Robiot: A Design Tool for Actuating Everyday Objects with Automatically Generated 3D Printable Mechanisms. UIST 2019.
[3] Li et al. Roman: Making Everyday Objects Robotically Manipulable with 3D-Printable Add-on Mechanisms. CHI 2022.
[4] Bolanos et al. MechaFormer: Sequence Learning for Kinematic Mechanism Design Automation. arXiv 2025.
[5] Heppert et al. CARTO: Category and Joint Agnostic Reconstruction of ARTiculated Objects. CVPR 2023.
Scene
Gear and Rack Bevel Gears Spur gears
Bounding Box
Reconstruction
Open