The process of captioning the results of computer graphics and visualization in 3-D CAD begins with the specification of the DotsPlus proposed standard for mathematical Braille typesetting.
The DotsPlus standard currently includes four fonts: 6-dot standard, 6-dot symbols, 8-dot standard and 8-dot symbols. The specification of each font includes an ASCII text description.
The formatted ASCII text description for the four DotsPlus fonts has been converted to the four Maya scene files, "dp6std.ma", "dp6sym.ma", dp8std.ma" and "dp8sym.ma". The meshes for each character glyph are grouped and accessed by the name of the character. The process of building these scene files is covered in the Open Inventor section of the DotsPlus 3D Tactile Model Production Pipeline.
Kern_DotsPlus.mel then reads a line of ASCII text, typed into the GUI TextField widget and for each character, it translates an instance of the corresponding font glyph to the next position on the line of output 3D geometry. It will be necessary to parse compositional tags to correctly position subscripts, superscripts, fractions and other mathematical formatting.
Square-root symbols, brackets enclosing fractions and other non-text raised lines will need to be generated procedurally and may need to be tightly integrated with the facility for applying captions to free-form surfaces.
The intent of tactile captioning in visual computing is to re-integrate with the physical model the symbolic statement of the abstraction it represents. This means applying text to a 3-D computer graphic surface mesh such that it becomes a unified CAD model which can be constructed via rapid prototyping, rapid tooling and/or rapid manufacturing.
Positioning Braille characters on a free-form surface is a painstaking task: Each dot must be positioned precisely for accurate readability and the text must flow across the surface in a sensible manner. It is not feasible to do this manually. The line of text must be positioned across the surface as a unit.
The line of Braille text is translated into the "local coordinate space" of a parametric surface using the DP_CreepNode plug-in for Maya.
Certain complications arise when attempting to pass objects from scientific visualization to rapid prototyping and manufacturing.
Once the buildable CAD model is joined with its set of captions, it is converted to the STL file format standard for the rapid prototyping industry and handed off for building.
Creating Tactile Captions in Three-Dimensional Computer-Aided Design Proceedings of the California State University at Northridge Technology and Persons With Disabilities Conference 2004.
Tactile Mathematics, Published in: "Mathematics and Art", Claude P. Bruter, Ed.; 2002: Springer-Verlag, Berlin. ISBN 3-540-43422-4. Proceedings of the International Colloquium on Art and Mathematics, Maubeuge, France, 20-22 September, 2000.
Stewart Dickson, Visualization Research Programmer Integrated Systems Laboratory Room 4355 Beckman Institute University of Illinois at Urbana-Champaign 405 North Mathews Avenue Urbana, IL 61801 USA