Final Update: 3D Printed Tactile Maps for the UW-Madison Engineering Campus

Hayden Eisenreich, Isabelle Hanson, Saketh Sridhara, Mikolaj Tyksinski, University of Wisconsin-Madison, Madison, WI

Abstract

The goal of this project is to create a tactile map of the University of Wisconsin-Madison (UW) Engineering Campus as an example for similar tactile maps across campus, other universities, and for other city layouts. Simple tactile maps exist for creation via 3D printing but lack essential details to be of value to a visually impaired user and are not ready for widespread adoption. Our design incorporates identifying braille text on a topological layout of the campus with scaled buildings to provide location landmarks for users. In addition, it details the different walking and driving paths available with unique identifiers and an associated key describing each landmark that can be found on the map. The goal of this design was to keep modelling and printing practices simple for general use, and this was accomplished by creating a base layout of the buildings and roads from a sectioned image of the UW campus. 

Design of the map uses a simple campus map layout with patterned features and extruded buildings. We considered multiple print processes, parameters, machines, and materials for this project. In addition to the campus layout, we implemented an accompanying key that details the complete building names and different identifying features of the map. Development through a series of trials and research led to the use of the Stratasys F370 machine with ASA (Acrylic Styrene Acrylonitrile) material, allowing for an accurate, durable model that could be produced quickly and at low cost. ASA was selected as the best material for meeting outdoor requirements of the project, such as UV, thermal, impact, and water degradation. 

In our design process, we utilized multiple feedback sessions with the McBurney Disability Resource Center to ensure legible, value-added designs. Our final design was found to be legible in both its braille reading and in relaying the topology of the region, and our test users were excited about implementation on campus as a next step. We also found that all printers could be used to create legible maps, expanding the viability of this type of modelling by allowing for useful maps with a large array of machines. 

Introduction

Accessibility is currently lacking on the University of Wisconsin-Madison campus with blind or visually impaired students frequently choosing other universities over UW-Madison. This was confirmed in an interview with members of the McBurney Disability Resource Center, and there are currently less than 5 blind students attending the university. We see this as a significant area in which our campus is lacking and an opportunity for our project to make a real difference. 

To that end, our project seeks to create accessible, legible maps that enlighten students with visual impairments about both the general layout and specific building names and locations for different areas of campus. Our maps seek to provide: 

  • Compass direction orientation 
  • General building layouts 
  • Topology of the area 
  • Individual building identification via braille text and a key 
  • Stairs, sidewalk, and road locations with appropriate, unique identifying features and key identification 

While simple tools like Touchmapper exist that can create quick topology layouts for areas with address input [1], they lack all the identifying features we are introducing to ensure usability. Our tactile map incorporates a wide variety of identifying features into the landscape topology to provide a full picture of a specific area of campus. Maps like this can also be quickly modeled and printed to cover different sections of the campus. The maps incorporate ADA recommendations, and even, more importantly, specific user feedback via the McBurney Disability Resource Center, ensuring designs that add real value and can be read. 

This project will use printers and processes currently available on campus via the Makerspace, particularly fused filament fabrication machines (FFF) such as Ultimaker and Stratasys models, and stereolithography (SLA) printers like the Formlabs Form 3 machine. 

Design and Modeling Process

The design process is intended to keep modeling simple and achievable for the entire UW campus. To model an area of campus, a specific area is sectioned via the University of Wisconsin-Madison Campus Map [2]. For our project we selected the engineering campus. The specific area can be observed in Figure 1 below. The campus map is quickly accessible to anyone looking to design a similar tactile map for a different area of campus, or even for an entirely different university. 

Figure 1. Sectioned image of the engineering campus used for our tactile map model.

To establish a base layout, the outlines of each building, road, path, and staircase are sketched line-byline directly over the image using SolidWorks 3D modeling. With this as a base layout, buildings are extruded according to relative heights using the number of floors as a reference. Specific relative heights could also be used but were not readily available for the campus. After extrusion, individual buildings are labeled according to a set of acronyms per Table 1 below. 

Table 1. Corresponding Building Names and Keyed Acronyms.

Key Name
ECB Engineering Centers Building
ME Mechanical Engineering Building
MSE Material Science and Engineering
ERB Engineering Research Building
1410 1410 Engineering Drive
EHALL Engineering Hall
PS Parking Structure

Labels follow ADA guidelines for braille character spacing and size [3]. These values can be seen in the example braille cell pattern in Figure 2. This pattern was easily copied onto both individual buildings and the key to create braille characters, again, proving the simplicity of our tactile map design approach in our aim that these can be quickly modeled across campus.  

Figure 2. Braille cell pattern based on ADA signage specs [3].

Print Trial 1

We began our print trials by printing our initial CAD model with the FFF technique, using the Ultimaker S5 machine at the Makerspace. For the first print, our objectives were: (1) ensure that the part is printable within 8 hours, (2) identify the potential printing failure modes, and (3) gauge print quality of braille. We used the Ultimaker’s PLA White material. The dimensions of the model were 245.4 mm x 162.3 mm x 42.5 mm, and it weighed 99 grams (costing $0.08/g).  To ensure fast print time, we used an extra fast print speed of 86 mm/s and a 20% infill rate. While the braille had been modeled as per the ADA standards, we wanted to ensure it could be printed as accurately as possible. Thus, we considered 3 printing layers for the braille (on the top layer). The printed tactile map is shown in Figure 3. 

Figure 3. Tactile map of the Engineering campus using the trial 1 print parameters and the FFF process.

While the tactile map accurately represented the heights of the engineering campus buildings, we observed that the FFF process could lead to serious issues with the braille accuracy under the parameters from trial 1. Specifically, we noticed that the braille font is no longer consistently circular, and there is also some intra-braille bleeding and overlapping characters with no/poor spacing (as can be seen in Figure 4). This leads to difficulties in reading braille, rendering these tactile maps unusable for the visually impaired. Also, the defects were not consistent across the part: braille characters on some buildings printed better and with fewer defects than the braille on Engineering Research Building. The printing resolution offered by the 0.4 mm nozzle at fast print speeds is neither reliable nor robust for braille applications, and we may further need to tune parameters such as print speed, layer height, and nozzle diameter to check if FFF is amenable for printing braille.  

Figure 4. Braille characters exhibiting loss of spacing, overlap with the initial Ultimaker FFF trial.

Another issue observed with print trail 1 is the flexing of the base of the tactile maps, as seen in Figure 5. This can lead to poor structural strength and breakage upon mounting or drops. This is less of a printing or material issue and can be attributed to the design thickness. Thus, this design issue was fixed with a thicker base plate for future trials. 

Figure 5. Flexing observed with the initial Ultimaker FFF trial.

Print Trial 2

The second trial that we conducted was printing a slightly scaleddown model using the Formlabs Form 3 SLA printer with Grey V4 resin. The size of our model for this trial was 137.4 mm x 90.9 mm x 24 mm. The cost of the material was $0.26/mL and the total time to complete was 5 hours and 30 minutes. As was previously mentioned, to print using the Form 3 printer, we had to scale down our model to fit within the build plate dimensions. Because of this adjustment, the braille on top of 1410 Engineering Drive was not included and the braille on top of most of the other buildings was closer to the edges than desired. Additionally, when slicing the STL file, the Makerspace staff suggested that we print our model using the auto-oriented angle and generate supports to reduce the force required to lift the cured part out of the resin vat. Following these suggestions and using the default settings for the Form 3 printer, we printed our trial 2 model, the top view of which is shown in Figure 6. 

Figure 6. Top view of the Formlabs SLA model.

As can be seen from Figure 6, the quality and fine detail of the print turned out quite well, particularly the braille, as it is accurately spaced relative to the other braille characters and does not run together like we saw in print trial 1. Additionally, upon touching the braille, you can feel each of the individual characters and clearly differentiate them from the top of each of the buildings. 

Although the quality of the braille and fine details of this print are favorable, there are a few drawbacks to printing with this process. First, upon closer inspection of Figure 6, you can see small ridges running perpendicular to the length of the part on the flat surfaces. While this may not be problematic to users without visual impairments, it may confuse those who are visually impaired as the surfaces are not completely smooth and consistent and could potentially be mistaken for a textured surface that we are not trying to convey. Another issue with printing using the SLA process is the build plate limitations previously discussed. As can be seen in Figure 6, the braille on top of a few of the buildings, particularly Engineering Centers Building, Engineering Research Building, and the Material Science & Engineering Building are much closer to the edges than initially intended. Additionally, you can notice the absence of braille on top of 1410 Engineering Drive. The lack of braille on this building along with the relatively small model are clearly an issue, while the other two drawbacks may or may not be issues for visually impaired users. Because it seems that the disadvantages of printing using this process outweigh the advantages that are observed, moving forward we will likely stay away from printing future models using the SLA process, at least with the specific size limitations of the machines available to us on campus. However, with machines with larger print volumes, this process may be worth further investigation. 

Print Trial 3

After our first two trials we decided to focus on the accuracy of the braille on top of the buildings while utilizing a larger scale, and faster print process than SLA. To do this more quickly we designed a test model consisting of only the parking structure with an additional test braille cell with all dots filled. 

We selected the Stratasys F370 FFF printer for this model run because its closed chamber helps to reduce the effects of the outside environment, allowing for better humidity and temperature control. In addition, the Stratasys features high accuracy, allowing layer thicknesses of 0.127 mm with ABS and ASA, and “accuracy of +/- .200 mm (.008 in), or +/- .002 mm/mm (.002 in/in), whichever is greater” [4]. The large build volume of the Stratasys at 355 mm x 254 mm x 355 mm exceeds that of even the Ultimaker S5, allowing for the model to be printed at its original scale or even be expanded upon if desired in the future. With this we do not need to sacrifice the design and size as is the case with the Formlabs SLA printer. Finally, the Stratasys allows for a wide variety of material choices, allowing for specific tuning for our application to outdoor use where UV, thermal, water, and impact durability are important.  

Results of the print can be seen in Figure 7 below. Accuracy is significantly improved over the Ultimaker FFF part, with clear braille characters free from any overlapping. In addition, filleted surfaces came out sufficiently soft on the edges. 

Figure 7. Isometric view of the completed Stratasys parking structure model.

Print Trial 4

Print trial 4 utilized the same simplified model of the parking garage as in trial 3. For this trial, we used an Ultimaker 3 FFF printer at the finest detail settings possible to determine if high quality braille could be produced. These settings consisted of a low print speed of 45 mm/s and 0.06 mm layer height with print time of nearly four hours. Figure 8 depicts the effect of different layer heights in the Ultimaker slicer. 

Figure 8. The left image depicts a layer height of 0.06 mm. The braille is printed in 9 layers allowing the spherical shape to be closely matched. The right image depicts a layer height of 0.2 mm. The braille is printed in 2 layers resulting in a non-spherical shape.

If settings optimized for quality can produce braille that is of acceptable quality, the Ultimaker machines could potentially be used to lower the overall cost of the project as Ultimaker filament is approximately four times cheaper than Stratasys filament. However, print time will be longer with the Ultimaker at these settings than the Stratasys. The results of trial 4 are depicted in Figure 9 below. 

Figure 9. The left image depicts the overall model. The right image is a close view of the braille characters. Merging of the characters is most visible in the bottom braille cell with 6 domes.

Even at the finest detail setting, there were still issues with the braille quality. Some individual domes merged creating legibility concerns. Our conclusion for this print trial is that the Ultimaker FFF printer is unable to produce prints of the quality we require for this project. 

Initial McBurney Center Feedback

To obtain feedback on the 3D printed tactile map trials, we worked with the McBurney Disability Resource Center. We met with two employees, one who works closely with visually impaired UW students and staff and another who is an access consultant that is a proficient braille reader. They were provided with all four 3D printed models. They were pleasantly surprised with the capabilities of 3D printing technology and were excited to feel these maps and remarked that this would be an extremely useful project in making UW an accessible campus. Specific to the printed models, the feedback is listed below:     

All the four models were readable. While we found the first trial with FFF to have overlapping and ‘squished’ braille, the reader was able to read it because of prior experience with worn out braille on books, public installations, etc. The SLA and Stratasys models (trials 2 and 4) were rated to be of superior quality and were preferred to the Ultimaker braille.  

Scaled building height feature: The braille reader was fascinated to be able to discern the height of buildings (previously unavailable in any tactile map/navigation tools such as Google Maps). They remarked that more information is always useful and makes a difference. The ‘You Are Here’ marker was also identified easily. The overall size of the tactile map (FFF model) was adequate; however, the SLA model (trial 2) was too small. 

Further, the following design improvements were suggested to enhance usability:

  • Walkways: Walkways would be more useful to braille readers than roads. The map needs to be scaled to incorporate walkways. 
  • North sign: To help orient easily, a north sign is to be included on the tactile map. 
  • Location of ‘You Are Here’ marker: The ‘You Are Here’ marker should preferably be located on the periphery of the tactile map at a location near a source of sound. 
  • Addition of key: The braille on top of buildings only includes the acronyms, therefore a supplementary key containing complete building names should be added. 
  • Consistency in surface finish: Some of the finishes on top of the maps (particularly the Ultimaker FFF) had inconsistent surfaces, which may lead to misinterpretation.

Final Design and Key

Based on the feedback from the McBurney Center and our experience with the first four trials, we chose the Stratasys F370 to print the final design and key. The accuracy of braille (without bleeding) when compared to Ultimaker, the larger build volume (over SLA), and the access to weatherproof material were key factors favoring the Stratasys printer. The changes to the CAD model included: addition of walkways and stairs (and a subsequent 20% scaleup), north indicator, and updated ‘You Are Here’ location to the corner of Engineering Drive and Randall Avenue. The walkways were indicated with dashed lines, stairs with dotted lines and roads with continuous lines. The final CAD model is depicted in Figure 10 and the print parameters are detailed in Table 2 

Figure 10. Final design isometric view.

Table 2. Final Design Print Parameters

Print Parameters
Process & Machine FFF: Stratasys F370
Material & Amount ASA
Cost $52
Print Time 12 Hours

The braille key requires hundreds of small sketch patterns to be repeated to generate the characters. SolidWorks ran extremely slowly on the lab computers, so we utilized Onshape, another CAD program, for the creation of the key. A black and white braille template was generated using a braille font in Word. A screenshot was then taken of the braille in Word, inserted into the drawing as a background image, and then each braille dot was individually selected and extruded. The braille template and sketch pattern are shown in Figure 11 below.  

Figure 11. Braille sketch pattern with an overlay of the desired braille characters.

After the braille was generated, sketch patterns for the road, stairs, sidewalk, and You Are Here indicator were added and extruded to match the map. The final CAD model of the key in Onshape is shown in Figure 12 below. 

Figure 12. Key overview.

Material Selection

With the Stratasys F370 we are limited to a few varied materials, particularly ABS, ASA, and PLA. Key requirements for our project revolve around its outdoor use: UV and thermal resistance given prolonged exposure to the sun especially on hot, long summer days, Water resistance given frequent rainy and snowy days with Wisconsin’s four seasons, and high impact resistance to survive abuse or weather elements like hail.  

With these requirements in mind, we selected ASA. Of the materials available it is considered UV-stable, resists fading and mechanical degradation, and has better thermal resistance than both ABS and PLA [5]. In addition, ASA exhibits high impact resistance and high water resistance [6]. However, it was difficult to find hard specifications or tests for these claims so an idea for future development would be to conduct a long-term outdoor durability test.  

Final Print Results

In printing our final design, we were pleased with good accuracy and surface finish throughout most of the part, however, some areas at the edges exhibited warpage and uneven finish. We are currently working with the Makerspace to improve the quality of our final ASA prints. According to Makerspace staff, there was a nozzle issue with the printer which caused uneven textures in the corners of the tactile map and key. This can be observed in our final prints as shown in Figures 13 and 14 below. 

Figure 13. Updated tactile map based on final design

Figure 14. Printed model of the key

Due to the nozzle issues, the braille in the bottom left corner of the map was unreadable. A close view of the printing defect is shown below in Figure 15. 

Figure 15. Print performance issue on the key

The print quality of the braille and buildings far away from the nozzle defects is exceptional. It matches the quality of print trial 3, which is what we expected for the entire part. The Makerspace has changed the print head and is working on printing new models, but they have not given us an estimated completion time. 

Second McBurney Feedback

After printing the updated map design and map key, we took both models back to the McBurney Disability Resource Center for another round of feedback. Like our first round of feedback, we met with an employee who works closely with visually impaired students who come to campus as well as an employee who reads braille. Both employees were pleased with our updated models and provided us with valuable feedback and suggestions that we could implement. 

The main suggestion they had was to switch the way we represented roads and sidewalks by making roads dashed lines and sidewalks solid lines. The reason that they suggested this was twofold. First, they found it more intuitive to have roads be represented by dashed lines because of the dashed lines that are typically present between lanes. Perhaps more importantly, the braille reader found the dashed lines more abrasive on her finger than the solid lines. Since people who use our maps will be more likely to follow the sidewalks than the roads, she preferred to have the sidewalks be smooth, so it felt better on her fingers and was easier to follow. Continuing with the feedback for roads and sidewalks, they also suggested raising the roads to be at the same height as the sidewalks and have both be more elevated from the base of the map to make reading and following them easier. 

To better differentiate the dotted line that represents the stairs on our map from the dashed lines, they suggested that we increase the spacing between the dots. Additionally, it was also suggested that we raise the height of the ‘You Are Here’ star indicator to be at least even with the height of the building that it is next to or even taller to make recognition and proper orientation easier. 

Additionally, we had previously been referring to the building at 1410 Engineering Drive as simply that in the key and 1410 in braille on top of the building. The McBurney employees informed us that this building is called Computer Aided Engineering (CAE) on their website, and they requested that we update the key and abbreviation to match this to be consistent with the information that was available to prospective and current students. They said that often, prior to coming to campus, students will reference materials on their website to familiarize themselves with buildings and areas, so it is important that our maps match the resources that students have available to them online. 

The last piece of feedback that the McBurney employees had regarding our map was that they felt that there was an inconsistent texture near the top of our map near Johnson Street. They felt, and we agreed, that this was due to the nozzle issues that the Makerspace printer was experiencing because it was only present at the top edge. 

With respect to the key, overall, they were pleased and found that the texture of the components was consistent and easily readable. The only issue that they had was that the lower left corner of the model was difficult to read due to printer issues that occurred. The key became unreadable after the ‘MSE’ line, but these difficulties only occurred in one area, thus we are hopeful that the Makerspace staff will fix the issues that they acknowledged with their printer, and we will be able to successfully print the full key in the future. 

Conclusions and Future Work

After four print trials and two design reviews with the McBurney center, we believe we have a polished tactile map and key of the Engineering Campus. The print trials allowed us to determine the optimal additive manufacturing process, machine, and machine parameters. We were pleased to find that even with lower quality prints like on the Ultimaker FFF machines, our braille was still legible. This expands the viability of the project greatly as it seems a wide variety of printers, including cheaper, hobbyist models, can create legible maps and at relatively low cost. The design reviews gave us insight on what visually impaired students, staff, and community members would find most beneficial, and helped us improve the overall usability of the design. They also revealed how important maps like this are, meeting a real need on campus to improve accessibility. As soon as the Makerspace completes defect free versions of the map and key we can work on the next phase of the project. 

The main future work that we are interested in working on is integrating our map on campus. Our group, along with the McBurney employees, feel that installing our maps on campus would be beneficial in improving accessibility at UW. After discussing how best to go about this with the McBurney employees, they put us in contact with Facilities Planning & Management here on campus to see where and how we would be able to install our maps. One of the locations that we agreed upon as a future candidate for installation was the corner of Engineering Drive and Randall Avenue. We feel that this is an ideal location as it is easily accessible near the entrance to the engineering campus and is also near an audible area that visually impaired users can use to orient themselves. We also believe that our maps could be installed at bus stops around campus as this would be an easy place for users to find and would allow us to integrate our maps across campus rather than just in the engineering area. 

In terms of installing our maps, the McBurney employees suggested that we mount the maps flat on an elevated stand that had protection from the elements rather than vertically on the side of a building. They felt that this would allow for easier orientation of the entire campus as users could quickly translate their location and movements from the map rather than having to account for the map being vertical on a wall. Additionally, the employees suggested that users be facing North when reading the map to allow for easier spatial orientation as visually impaired people tend to rely on cardinal directions for orientation and movement. 

Aside from working with Facilities Planning & Management to install our map on campus, there are a few additional areas of future work that we are interested in. First, we would like to develop similar maps of other areas of campus, such as near Bascom hill and Observatory hill, so accessibility could be expanded and improved beyond engineering campus. Expanding our maps to include other areas of campus would introduce the challenge of identifying non-UW buildings, however, we believe that this could be done by including another identifying marker on the maps as well as in the key. Additionally, we believe that a fantastic application of our 3D printed tactile maps would be developing temporary maps of campus so users could easily identify areas that were under construction and navigate them quickly. The use of 3D printing processes would be a great fit for an application like this because it is quick and inexpensive. The last area of future work that we are interested in exploring is conducting a long-term outdoor durability test with the ASA material to see how it holds up under UV exposure, rain, and potentially even snow. We believe that conducting this test would be beneficial to installation on campus to understand how long our maps would last and to develop a schedule for potential replacement, so the maps do not lose their readability. We hope that our maps can help improve the campus experience for the visually impaired and we feel that this has been incredibly rewarding work. 

References

  1. Kärkkäinen, S. (n.d.). Touch Mapper. Touch Mapper – Tactile Maps for the Visually Impaired. Retrieved February 27, 2022, from https://touch-mapper.org/en/
  2. University of Wisconsin–Madison Campus Map. Campus Map. (n.d.). Retrieved February 27, 2022, from https://map.wisc.edu/s/x801uir5
  3. Accent Signage Systems, Inc. (2012). Quick reference guide to ADA signage.
  4. “Stratasys F370.” Objective 3D, https://www.objective3d.com.au/stratasys-f370/
  5. Stratasys. (n.d.). ASA: A UV stable 3D printing material. Retrieved April 24, 2022, https://www.stratasys.com/en/materials/materials-catalog/fdm-materials/asa/
  6. Lambert, K. (2020, November 12). Why asa filament is best for outdoor application. MakeShaper. Retrieved April 24, 2022, https://www.makeshaper.com/2020/11/12/why-asa-filament-is-best-for-outdoor-applications/