Tactile Problem/Solution Bank Project

Contributed by
Ultimaker in partnership with MatterHackers

3D modeling and printing should be accessible to every educator because 3D printed models provide an affordable alternative to purely visual images, offering  students a tactile means to understand spatial and other concepts.

Whether it is the creation of models and manipulatives, the conversion of 2D images to 3D tactile objects, or the ability to place Braille on designed objects, 3D printing allows teachers, and specifically teachers of the visually impaired, to have personalized learning aids that empower them to improve the learning experiences of their students.

This community project started with designing tactile models for the visually impaired, but it is also about using design to ensure that teachers have access to educational materials that are accessible regardless of learning styles, physical, or sensory abilities. So if you're not sure that your model is 100% appropriate for a visually impaired student, we still encourage you to submit your solutions if you believe they can help other students understand a concept, lesson or idea.

The Tactile Problem/Solution Bank project is evolving aims to address the following topics:

• Education — To learn about the best practices for designing tactile objects for the visually impaired.

• Submission — To provide a way for teachers of the visually impaired to share their needs for specific models and for models that help explain specific ideas.

  Request a model by submitting it to the Requesting a model from the Tactile Problem/Solution Bank.

• Application — To apply those best practices to design so that  visually impaired students and others can explore specific ideas.
• Share — To publish, share created models on Youmagine.com, to tag them with  #tactileSolution, and  to link to it from Benetech's ImageShare.

This page will be a living document. As resources are created and best practices are refined, this page will continue to update.

This project will be ongoing.

Requested Models

Submit your solutions:

When you have designed a solution and posted the STLs on Youmagine with the tag #tactileSolution, please complete this form.

Activities:

Do you have an activity that should be added? Submit it here.

Best Practices

This is an evolving resource that we hope will develop as this project evolves.

Ideally 3D printed models should be:

• Easily reproducible.
• Volumetric— if you are just creating an extruded version of a 2D graphic, is there another way to create this model?
• Modles that make the Untouchable touchable
• Models should capture ideas that cannot be easily conveyed by other means:
  • Scanned objects that are not easily accessible: artwork, body parts
  • Math equations in 3D dimensions
  • Microscopic objects
  • Very large objects

Things to Consider:

• Size

  Don't make the model too small. If possible, make your model same size of the actual object.

  Use a reference scale symbol - with real comparison - bigger than a house, bigger than cell phone, about the size of a fly, etc.

  Tactile Perception Limitations

  • Resolution of human fingertip is 25 dpi
  • Tactual field of perception is no bigger than the size of the fingertips of two hands.
  • Color information is replaced by texture information.
  • Visual bandwidth is 1,000,000 bits per second, tactile is 100 bits per second.

• Symbols

  Can you use symbols to indicate orientation, scale, weight?
  For example, is your model the size of a fly or house?

• Resolution—fingertip vs pixel
• Orientation
• Min/Max height for raised object

  Higher things need more space around them to help discern things that are lower in height and in close proximity.

• Perceptual details

  What is the minimum size?

  What is the minimum spacing

• Weight

  Can you make the model have the same weight as what it represents, or can you provide information about the scale?

• Durability

  These objects are touched and felt by hands and should not have parts that can easily break off.

• Parametric

  Can someone easily change your model?

• Metadata

  Include useful information (grade level, subject(s), material, dimensions, color)

• Wall thickness

  What thickness is too thin?

• Edge treatment  

  Models should be harmless to touch.

• Use of braille (resist putting braille on object - use a symbols instead)
  • orientation/direction of braille
  • size of braille
  • placement or offset from edge

• Printing Braille on 3D Models — From Jim Allan at the Texas School for the Blind

  The article Printing of Braille with 3D printers showed that in order to achieve quality 3D printed braille the braille must be printed perpendicular to bed of the printer. Braille printed at other angles can be difficult to read.

  Problems

  • Spacing - Designer does not leave enough space to read the braille - Braille reading is a dynamic process. The reader’s fingers must move across the braille to read it. There should be no interfering lines, objects, textures, etc. within 10mm (TAME) of the braille on all sides.
    • inset - The designer places braille too close to edges of model and this interferes with the reading of the braille

  • Orientation - braille make sense when oriented properly. On a 3D model the user can get confused orienting the object and the braille does not make sense. Additionally, the braille orientation should match the preferred orientation of the object.

  Solutions

  • Designers should provide space on the model for embossed braille that can be added to the model after production.
    • Braille Labeler
      • http://www.braillebookstore.com/Handheld-Braille-Labeler.1
      • https://www.maxiaids.com/search?q=dymo+braille+label+maker&pagesize=12

    • Peel and stick label paper for braille writer
      • http://www.braillebookstore.com/Braille-Labeling-Sheets.1
      • http://www.americanthermoform.com/product/braille-labeling-materials-braillables/

    • Provide space on model for raised symbols for use with a key
      • Feel and Peel stickers
      • http://www.braillebookstore.com/Bump-Dots.1
      • https://www.maxiaids.com/braille-tactile-voice-markers
      • Self-adhesive felt or cork symbols
        • https://www.michaels.com/creatology-peel-and-stick-felt/M10572180.html

      • Print raised symbols on the model
        • Choose symbols from the following
          • Circle (outline and filled)
          • Square (outline and filled)
          • Triangle (outline and filled)
          • Asterisk (star *)
          • Chevron (^><
          • Union symbol U

        • Symbols to be minimum width of 13mm (TAME)
          • Minimum height 1.6mm
          • Outline shapes - minimum outline width .8mm
          • Audio feedback.- bluetooth or haptics.

Additional Links to Best Practices

• Braille Authority of North America's Guidelines and Standards for Tactile Graphics PDF version

  Different types of lines, styles, graph, and map standards from BANA converted from point to mm.

  
  

• Braille Authority of North America's Guidelines and Standards for Tactile Graphics, February 2012 Web Version

  Different types of lines, styles, graph, and map standards from BANA converted from point to mm

  
  

• California Community Colleges at the

  Foothill-De Anza Community College District's Creating Tactile Graphics

  A good set of guidelines and best practices regarding creating tactile graphics from the High Tech Center Training Unit of the California Community Colleges

  
  

• Tactile Book Advancement Group's (TBAG ) Best practice guidelines for the design, production and presentation of vacuum formed tactile maps

  
  

• Smarter Balanced's Tactile Accessibility Guidelines

  A 16 page guideline on how to make different types of tactile graphics accessible. Mainly math and graphs.

  
  

• Smithsonian's Guidelines for Accessible Exhibition Design

  
  

Standards

Braille Standard

Common Braille characters are based on a 6-dot cell having two columns of three dots. If the empty cell is counted as the space character, 64 unique dot combinations are possible with a six-dot cell. Dot height is approximately 0.02 inches (0.5 mm); the horizontal and vertical spacing between dot centers within a cell is approximately 0.1 in (2.5 mm); the blank space between dots on adjacent cells is approximately 0.15 in (3.75 mm) horizontally and 0.2 in (5.0 mm) vertically.

Minimum Line Height – 1.6mm (TAME), braille dot height – 0.5mm

Line styles in Appendix F of BANA Tactile Graphics Guide (note: converted to millimeters)

Arrowheads

3.4.3.7 – If an open arrowhead is used, the two sides of the arrowhead should be an equilateral triangle with the two sides being the same length as the undrawn base. The shaft of the arrow should be spaced 3.3mm from the apex.

The shaft of the arrow should be at least 19 mm long. If the shaft of an arrow is too short the item may look like a point symbol rather than a direction indicator.

   

Circle Graphs

6.3.3 – The outline of the circle should be tactually distinct from the lines separating the divisions.

   

Clock Face

Circle: 0.4 stroke/3mm dash/1.5mm gap, butt-capped

5-minute ticks: 0.8mm stroke, 12.5 mm either side of circle

Numbers: 6.5mm distance from ticks

Hour hand: 2.1 mm stroke with 4.2mm gap, round-capped

Minute hand: 1.5mm stroke

   

Grids & Graphs

   

Gridlines should be the least prominent lines on the graph

0.3mm stroke; 0.6mm dash; 1mm gap

Axis lines should be stronger than gridlines and include arrowheads at outer end (follow print whether double- headed or not)

.8mm stroke; solid line

Plotted line(s) should be tactually the strongest line(s) on the graphic

1.5mm stroke; solid; if line is dashed in print, make it dashed

Point of origin (O) should be included only if it is shown in print

Sometimes it is the letter O; other times it is a zero—follow print

Y label placed above (preferred) or to the left of arrowhead

X label placed at end (preferred) or above arrowhead

   

If space is needed, some numbers may be omitted from graph

Always attempt to show at least one axis number for reference

Numbers are placed to left of y-axis and below x-axis

No number indicator used for x- or y-axis coordinate numbers

Dots 1,2,3 should align with vertical grid lines/ ticks (ignore minus sign) and align dots 2,5 with horizontal grid lines/ticks

   

Shaded regions should be distinct to recognize but not overpower plotted lines or vertices

Resources

• Tactile Design Project
• The education model exchange

  Development of 3D printable model files for education for the visually impaired and other tactile learners. See hackaday.io for details and caveats.
  
  

  To learn more about the purpose and development of this project, see  hackaday.io's 3D Prints for teachers of the visually impaired

  
  

• DIAGRAM' Center's  Decision Tree,  a tool for choosing which print images need tactiles and which need descriptions:

     

  

  The open-source image sorting tool

  Also keep in mind:

  • Timeframe to create vs Time in use
  • Time model needs to exist.
  • Class model.

  
  

• The following chart was published in Benetech’s 3d printing for Education

  Quick Start Guide and was created by Lucia Hasty, a teacher of the visually impaired, and can be used to determine when a 3D model can support learning:

  Disability	When a 3D model helps	When a 3D model does not help	Notes
  Blind/low vision	When actual object is not available to explore through touch (too small, large, fragile, dangerous, not in proximity) When process, stages, progression are involved When moveable and/or removable parts are incorporated (e.g. model of the eye, electricity through a circuit) Color contrast helps learner with low vision distinguish the components of 3D model	As a stand-alone source of information When 3D attempts to duplicate a 2D image When results are 2.5D — not fully 3D	If the learner has never experienced the actual object, they will not be able to recognize the 3D model. The 3D model requires verbal explanation about details and features. The actual object will have different textures than the 3D model. The size and proportion of the actual object in comparison to the 3D model are difficult to project. If the model orientation is less than 360 degrees, the learner needs to know the view.
  Deaf or hard of hearing	When learner also has a reading deficit that results in difficulty understanding a caption or other written material in relation to actual object When learner has difficulty understanding sign language interpreter's explanation When learner's first language is not English/ASL	When learner has same access to object as other students and meets their needs for comprehension
  Deafblind	When real object is not available to explore through touch (too small, large, fragile, dangerous,  not in proximity When process, stages, progression are involved When moveable and/or removable parts are incorporated (e.g. model of the eye, electricity through a circuit Color variation helps learner with low vision distinguish the components of 3D object.	As a stand-alone source of info When 3D attempts to duplicate a 2D image When results are 2.5D- not fully 3D	If learner has never experienced real object, will not be able to recognize it. Requires verbal/sign explanation about details and features. Real object will have different textures than 3D model. Size and proportion of real object in comparison to 3D object are difficult to project. If orientation is less than 360 degrees, learner needs to know the view.
  Learning disabilities	Learner with visual functioning difficulties will be able to have a hands-on opportunity to examine and manipulate object being taught more thoroughly Learner with auditory processing difficulties will be able to examine up close, ask questions, listen to directions/instructions while having the opportunity to manipulate object	When object is not available for close-up examination and manipulation, but just for viewing at a distance	Each student with learning disabilities has different skills. Encourage the student to use the 3D object as needed for a better understanding. The opportunity to ask questions and have discussion is very important in gaining understanding
  Physical disabilities	When actual object or parts of it are not accessible for viewing When using technology (e.g. microscope) is difficult for motor abilities	When the actual object is not available for examination and manipulation	Physical disabilities may include: mobility, motor skills in hands, balance, etc. The learner should be accommodated for specific needs. Each learner with physical disabilities has different skills. Therefore, Encourage the learner to use the 3D model as needed for better understanding.

  
  

  
  

• Visually-impaired touch

  
  

• Three-dimensional tactile symbols produced by 3D Printing: Improving the process of memorizing a tactile map key

  For practitioners, this article provides data about the possibilities of 3D Printing applied to tactile maps, keys, and symbols.

  
  

• Tactile Graphics Kit

  
  

• Tactile Graphics Image Library

  
  

• Tactile Library Web Site

  
  

• 3D Models - 3D printable

  
  

• California Title 24 – Restroom Signs - compliance Signs

  
  

• How To Make Tactile Maps Discriminable For Touch? by Dr. Yvonne Eriksson

  
  

• Improving Tactile Map Usability through 3D Printing Techniques: An Experiment with New Tactile Symbols by Jaume Gual Ortı´, Marina Puyuelo Cazorla, and Joaquim Lloveras Macia

  
  

• A Pilot Study On the Discriminability of Tactile. Areal and Line Symbols For the Blind by G. A. James* and J. M. Gill

  
  

• Printing of Braille with 3D printers - DIAGRAM Center

  
  

• The recognition of 3D basic patterns and tactile icons for the blind by Yu-Cheng Chen1, Chun-Hsien Chiang1, Huan-Chung Chiu

  
  

• Tactile Maps as Navigational Aids by Heamchand Subryan, M.Arch/M.F.A., IDeA Center, SUNY Buffalo

  
  

• University of Oregon Tactile Map Editor A User Guide and Tutorial

  
  

• Tactile Drawings

  
  

Have a resource that should be added to the list? Add it here.

Software

• Text to 3d printable Braille
• Braille OpenSCAD Font Module by drayde
• KitWallace/openscad
• Lumi Industries Braille text converter
• Braille OpenSCAD Font Module
• TouchSee!

Inspiration

   

Fixed Volume Objects

by Whosawhatsis

Hackaday.io: 3D Prints for Teachers of the Visually Impaired

   

The Six Crystal Families

by GeoFabLab

   

Unit Circle with Braille

by collegeofthedesert

   

Tactile Goodnight Moon

by TactilePictureBooks

   

Haptic Device Offers GPS Navigation for the Blind

Article by Meghan Brown at engineering.com

   

Wave Patterns for Red and Blue Light and several other models

Models by Professor Steven Sahyun and students from University of Wisconsin - Whitewater

Here are resources for two models on LibraryLyna that include how-to-use guides:

   

World Religion Chips How To Guide

   

Disk Method How To Guide

To see the introduction to this project, go to the The Tactile Problem Community Project blog post.