A Demonstration of Molder: An Accessible Design Tool for Tactile Maps
Lei Shi, Yuhang Zhao, Elizabeth Kupferstein, Shiri Azenkot · 2019 · Proceedings of the 21st International ACM SIGACCESS Conference on Computers and Accessibility (ASSETS 2019) · doi:10.1145/3308561.3354594
Summary
This demonstration paper presents Molder, an accessible design tool that enables teachers of the visually impaired (TVIs) and orientation and mobility (O&M) specialists to create 3D printed tactile maps without requiring professional 3D modeling skills. The problem Molder addresses is significant: tactile maps are essential tools for helping students with visual impairments learn about geographic areas and navigate independently, but creating them currently requires modeling software like Rhino or Blender that relies on visual GUIs, demands professional training, and is inaccessible to designers who themselves have visual impairments. Molder replaces the conventional screen-based 3D modeling workflow with a tangible interaction approach. A designer enters geographic coordinates on an accessible website to generate a draft map model, 3D prints it, then places the printed model on a Physical Ruler — a platform with fiducial markers that allows the Molder iOS app to track the model’s position via computer vision. Instead of manipulating objects on screen, the designer selects buildings by touching them directly on the printed model and chooses functions by touching printed tangible buttons (Tactile Widgets and Function Widgets). The system provides both auditory feedback and high-contrast visuals throughout the design process.
Key findings
Molder implements eight core functions through its tangible interface: creating a draft model from geographic coordinates, adding braille labels, adding tactile patterns (raised lines, dots), adding icons, building deletion, model scaling, undo, and adding audio labels. The Tactile Widget offers four tactile feature options (Braille, Icon, Line, Dot) and the Function Widget provides four operations (Label, Delete, Scale, Undo), all represented as tactile objects with trackable markers. The system architecture splits between a Molder App (iOS, handles computer vision tracking and user feedback) and a Molder Server (implemented as a Blender add-on that processes model data using Python scripts). An interaction mode allows end users — students with visual impairments — to explore completed models and retrieve audio labels by touch. The Physical Ruler uses orthogonal rulers with three markers for model positioning and twelve slots for tangible widget placement, along with an Indicator rectangle for the scale function. The approach of directly manipulating a physical 3D printed model rather than a 2D screen representation fundamentally changes the accessibility of the design process.
Relevance
Molder addresses a critical bottleneck in tactile graphics production: the people best positioned to create tactile maps for students with visual impairments — TVIs and O&M specialists — are often unable to use existing 3D modeling tools because they lack professional training or have visual impairments themselves. By shifting the design interaction from screen-based to tangible, Molder makes the creation of customised 3D printed tactile maps accessible to non-expert designers. This is particularly important given the growing availability of 3D printers in schools and the demonstrated benefits of 3D printed maps over traditional tactile graphics. The tangible interaction paradigm — selecting objects by touching the physical model and choosing functions via physical widgets — could be applied beyond maps to other types of 3D accessible content such as globe models or architectural layouts. As a demonstration paper, Molder is a proof of concept that has not yet been formally evaluated with target users, which the authors identify as future work.
Tags: tactile maps · tactile graphics · 3D printing · visual impairment · orientation and mobility · tangible interaction · design tools · accessible authoring · braille