Gen_braille: Development of a braille pattern printing method for parametric 3d cad modeling

Abstract

The aim of this research is to establish a method that visually impaired people can use for shaping three-dimensional (3D) objects by themselves using programmable computer-aided design (CAD). In parametric CAD, variable definition and substitution are devised in a source code of the programmable CAD. If we prepare 3D data of assistive technologies (ATs) with the source code of the parametric CAD and also prepare an intuitive user interface for variable substitutions, we can realize a do-it-yourself AT useful for many visually impaired people. Thus, it is effective to place braille on the surface of a modeled object and use the 3D model as an AT for the visually impaired people. In this research, a CAD module called gen_braille was created for the OpenJSCAD software. When an arbitrary braille character string is provided to this model, it outputs corresponding 3D dot patterns. The aim of this research is to realize a braille generation system that can be used for parametric CAD; therefore, a required area calculation function was implemented. The author was able to produce an output of 32 square plates having sides of 2 cm each that displayed a single braille character. Debris, which could be misread, had adhered to 25 print results. The mean of the amount of the adhered debris was 1.08 (SD = 0.93). The debris could be removed with an ordinary post-printing process called manual removal. To prove that gen_braille could be used in parametric CAD, the tactile braille ruler creation system was made. By changing the value of the unit variable, it was possible to output a ruler with a freely chosen unit system (metric or inch).