Affordable rapid 3D printing technologies have become key enablers of the Maker Movement by giving individuals the ability to create physical finished products. However, existing computer-aided design (CAD) tools that allow authoring and editing of 3D models are mostly visually reliant and limit access to people with blindness and visual impairment (BVI). Through a series of co-design sessions with three blind users of mixed programming ability, we identify accessibility challenges in existing 3D modelling scripting tools and design interactions to support dynamic feedback of scripts using a 2.5D tactile shape display. With these insights, we implement shapeCAD. Interacting with shapeCAD, BVI users are able to leverage the low resolution output from a 2.5D shape display to complement programming of 3D models. shapeCAD allows users to haptically explore and modify existing models, and to author new models. We further validate usability and user experience through an evaluation with five BVI programmers. In a short period of time, novices were able to design a range of new objects. BVI users can bring a valuable perspective to design and it is imperative to increase accessibility in tools that enable this community to also participate as designers.

Spatial layout is a key component in graphic design. While people who are blind or visually impaired (BVI) can use screen readers or magnifiers to access digital content, these tools fail to fully communicate the content's graphic design information. Through semi-structured interviews and contextual inquiries, we identify the lack of this information and feedback as major challenges in understanding and editing layouts. Guided by these insights and a co-design process with a blind hobbyist web developer, we developed an interactive, multimodal authoring tool that lets blind people understand spatial relationships between elements and modify layout templates. Our tool automatically generates tactile print-outs of a web page's layout, which users overlay on top of a tablet that runs our self-voicing digital design tool. We conclude with design considerations grounded in user feedback for improving the accessibility of spatially encoded information and developing tools for BVI authors.