Project Core’s Tactile Symbols
Project Core is a program of the Center for Literacy and Disability Studies at the University of North Carolina-Chapel Hill. They have established a Universal Core Vocabulary as part of their Universal Core Communication Systems. They describe the Universal Core Vocabulary as: “a set of 36 highly useful single words that can be used alone or in combination to communicate for a range of purposes on countless topics with a wide variety of communication partners.”
In support of their Universal Core Vocabulary, Project Core developed a set of thirty-six, 3D-printable, tactile symbols, for use with individuals who are blind or visually impaired and have complex communication needs due to additional disabilities. Project Core makes these symbols freely available to the public as STL files. The symbols are shaped according to a fixed set of rules:
For example, adverb symbols are circular in shape, have bumps around the edge, and should be printed using yellow filament. Adjective symbols are heart shaped, with smooth edges, and should be printed with blue filament. And so on… Note that there are no nouns or interjections among the 36 core words so Project Core doesn’t offer any examples of what these symbols would look like.
The concept of creating 3D-printable, tactile symbols is very clever! Unfortunately, the implementation leaves much to be desired.
The upper surface of each symbol has a unique, raised, tactile shape along with printed Braille and engraved text of the associated word:
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| “Like” symbol | “Get” symbol |
The raised tactile shape on the “like” symbol is 4 half-cylinders of varying lengths. The raised shape on the “get” symbol is shaped like a cresting wave. The engraved text seems to be placed wherever there’s space – even being cut into the raised shape, if necessary. Are these raised shapes representative of the word they support? It’s hard to see a connection.
In fact, many of the shapes appear entirely arbitrary. Here are four of the symbols that incorporate raised dots (other than the Braille) as the tactile discriminator:
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| “I” | “help” | “more” | “you” |
The two dots of the “I” symbol are apparently repeating the Braille for the letter “i”. The five dots on the “you” symbol are probably taken from the Braille for the letter “y” – if held in the correct orientation. Rotate the symbol 180 degrees and the dots represent the Braille symbol “&” or the word “and”.
And what about the remaining symbols? Why is “help” represented by six dots and “more” by three? Why are the dots raised higher on the inner two symbols than on outer two? Maybe we shouldn’t be thinking of them as mapping to Braille if they are tall and thin?
It’s not at all clear what rules are defining and unifying the raised shapes:
| Why does a hollow cylinder correspond to the concept of “to do” while a solid cylinder corresponds to the concept “to turn”? |  |
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| Why would three ramps correspond to “finished” and an upside-down “to get” shape represent “to want”? |  |
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| We understand how putting a hemisphere inside of a container could represent the concept “in/inside” but why would changing that shape to a cube represent the concept “to put”? |  |
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| Arrows need to be used carefully. It’s reasonable to use a right-facing arrow to represent the concept “to go” but why would two downward-facing arrows represent the concept “can”? |  |
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If a shape is arbitrary then one can only learn its relationship to its referent through rote memorization. It’s not at all clear how many possible unique arbitrary tactile shapes can be defined that are both unique and tactilely discernable. This is why tactile shapes must be based on a set of rules that ensure that shapes are inherently meaningful and internally consistent across the set.
Visual iconicity doesn’t necessarily translate well to tactile processing. People with visual abilities may be able to interpret the image below as a pair of eyes. The eye-lids make the image even more visually recognizable as eyes, but for individuals exploring the graphic via touch, they will perceive those elements simply as a multi-height shape with confusing contours. And is that an arrow or a nose? At first “glance” it looks like a nose and makes you think that the graphic represents the concept of “face”. On second thought, the arrow is probably intended to represent “directed sight” and therefore the concept of “to look” – though the arrow doesn’t extend forward from the direction in which the eyes are looking.
Why Braille?
We question the decision to put Braille on the face of these symbols for two reasons. The first is that 3D-printers cannot create a small bump very well. The top of the bump tends to just be a small blob of plastic that is often rough and sandpaper-like. The second, and more fundamental reason is that we question the applicability of Braille for this audience. Someone with complex communication issues is unlikely to be ready to learn a specialized encoding of a written language. If the Braille isn’t relevant to this audience then it’s just a tactile distraction making conceptually processing the symbol unnecessarily complex.
Printability
What the Project Core tactile symbols definitely have going for them is that they are “tactile”. Unfortunately, they sometimes achieve that end by being difficult to 3D-print. For example, the portion of the “Get” symbol that is circled in yellow below is impossible to print without supports. And the portion outlined in black will be very fragile. It will snap-off as soon as it encounters a minimal force.
What’s the alternative?
We believe a proper alternative to the Project Core 3D Symbols can be encapsulated in three words: flexibility, extensibility, and simplicity.
Flexibility
Project Core provides their 3D symbols freely but only in STL form. That means that it’s difficult or impossible to resize the symbols if you want to use them for other purposes. Want a set of symbols that are thinner and smaller? You can scale the STL file in your slicer program but the graphic, text, and braille will probably be distorted.
What if you want to organize the symbols around a different concept than “word class” or what if you just want to simplify things by limiting the symbols to a few geometric shapes? Again, STL files are static and difficult to edit.
Finally, if a particular graphic is confusing, or if the text or braille is distracting, you can’t change or get rid of them because… well, because of the STL format…
Extensibility
Project Core doesn’t believe that they have provided every tactile symbol that you’re going to need, but at the same time, they don’t make it easy for you to extend their symbol set. You’re pretty much on your own. You’d need to learn how to use a 3D modeling (Computer-Aided Design) program and try to replicate all the shapes and characteristics (edge treatments) of the core set.
Simplicity
We believe that there’s just too much information vying for space on the face of the Project Core 3D symbols. The face of their symbols include: a raised graphic, engraved text, and Braille text. We question whether the engraved text is necessary – especially if it’s only intended for use by the sighted communication partner. We question whether Braille is appropriate given the severely limited communications skills of the users, and whether it will be a distraction to the user who is tactilely exploring the raised graphic.
As a result, we’ve chosen to simplify the structure of our tactile symbols. By default, the face of the symbol is completely dedicated to the raised graphic. If you want to include engraved text, that is placed on the back or sides of the symbol where there will be more space and where it won’t interfere with the graphic (note that you can place engraved text on the face of the symbol if you think that’s necessary). If you believe that Braille is important to using the symbol, it prints much better on a vertical surface than it does on a horizontal surface, so printing on the sides, produces the best Braille. So, we support you in putting Braille on the vertical sides of our symbols (but again, you can place the Braille on other surfaces as well).