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Working with and 3d scanning LIDAR apps for accessibility review in iOS

by Anson Parker on 2021-07-26T21:25:00-04:00 in Multidisciplinary | 0 Comments

As a collaborator in the Lyrasis Catalyst 2021-2022 award with the Science and Engineering Library we are pleased to produce our first documentation in the series done in collaboration - Accessibility Information and Disability Inclusion professionals

Our goal working with Visitable was to look at our spaces from a wheelchair accessibility perspective and consider which apps provide the simplest workflow for accessibility professionals to use when working with the LIDAR equipped iPad Pro 12. 

<TLDR> 3d scanner app is a convenient off-the-shelf app you may use with confidence.  All the features are free, and you're not locking yourself in from a file-format perspective. All that and it has some convenient workflow features for working with accessibility professionals.

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Notes from

July 13th I went scanning with Joe Jamison - founder of All of the scans were done with the 3d scanner app, and most are posted here for review  Starting at the front of the library and working our way down the elevator and in to the bathroom and group study rooms we worked to evaluate 3d scanning in the context of space accessibility analysis.  Here are Joe's notes  


3d scanning strengths:

  • Can get a full picture, and get overall takeaways
  • Easier to view depth
  • Quicker for making measurements (if knowing where and how to scan) and giving feedback
  • Easy to share with colleagues, customers, and users to review and make their own measurements if they'd like

Manual testing strengths:

  • Small details and barriers are easy to see
  • Measurements are more accurate, helpful for measuring small lips and door thresholds
  • Pictures are a more efficient way to help users see a holistic view rather than scanning a full room
  • More thorough, includes looking at attitudinal barriers as well as asking clarifying questions on policy and practices

3d scanning weaknesses:

  • Might be difficult or impossible to see small details, such as door thresholds
  • Visualizations aren't as clear as pictures: reflective surfaces distort shapes, corners are not clearly defined, etc.
  • Might be a learning curve to figure out where and how to scan, which is a little harder to communicate than providing instructions on where to take pictures
  • Scanning roofs/ceilings and bigger spaces for visualizations takes longer than pictures
  • Some tools, such as the Sketchfab lab tool, do not make it easy to measure within units desired
  • Cannot measure slope or door pressure with existing tools

Manual testing weaknesses:

  • Slower to take measurements and record them - makes overall process of pictures and measurements slower
  • More steps in the process to share reviews with customers, colleagues, and users
  • Taking measurements with a tape measure is potentially less accessible/ more difficult than scanning an area

3d scanning 101

We downloaded about a dozen different 3d scanning apps, and most of them required paid subscriptions - i went through the free trials on several other tools, but really wasn't impressed and everything came in to a toss-up between two great products on the closed source side, and then the open source tool that comes from the robotics space and that shows strong potential for bringing game-changing developments in to the accessibility space.

Off-the-shelf Winners

For working offline and general flexibility + user interface there's no question - the 3d scanner app is your go-to app.  Use the low resolution to capture large spaces, or dig in to a single room or two at a time with the high res tool.  You can export the file a bunch of different ways and do any technical analysis you want, and exporting to the web is simple is a collection of scans done in the library and seems to work ok in the new Sketchfab lab tool here  Familiarity with some 3d viewing tools is still going to be a plus, and for users who are comfortable in sketchup or other architectural tools the additional controls are available for you to work with. in the labs tool here!/models/0b64b75eea1c40a88aec4f021f7389ae

their measuring tool correctly shows the distance in our men's room between a shelf and a wall at 83cm which is right on the cusp of being too small for a wheelchair to pass

sketchup 3d measuring tool


For convenience a with just measuring spaces is a solid contender.  It only allows you to post 3d scans to the web, but it comes with some convenient measuring tools and this model of a hallway in the hospital was one of the first scans I took and the interface is intuitive and elegant.

polycam's 3d scanning app has some measuring tools built in


Open Source and Robotics Perspective 

Also tested but not ready for a full review is RTAB_MAP.  This is an important tool for the next part of our discussion which is a more automated approach to the analysis and looking at accessibility from a robotics perspective.  This has the capacity to tie in to epic large scale products, and being the only open source tool I've seen for processing LIDAR in the iOS ecosystem it is by far the most interesting tool to test.  With an active forum, 260 open issues and 463 closed issues on github it is a very active community with incredibly technical leaders in the LIDAR processing field. 


  3d scanner app rtab_map
Scanning interface the low polygon scan does a great job on large areas and is intuitive, the high res "paint" approach is clumsy in large spaces. High res version doesn't show you where you've already been well best interface - the light blue to polygon camera change is intuitive

the point cloud interface is useful for showing people exactly what the machine sees at the most basic level, and from a training perspective is a great place to begin a training session.  The pose overlay data is helpful for explaining that dimension of mapping.

Web File Sharing you can updload directly to none
Stability crashes occasionally, but pretty good. really solid crashes a lot. on the ipad i found myself stopping it when it said memory was at around 800mb
File formats excellent choices none - web based publishing only, paid subscription unlocks other formats has a pbstream.db format that saves pose data. also offers point cloud exports
Community discord, forum, github

Accssibility notes need to test need to test

the fact that this tool is harder to use for sighted users actually reinforces the idea that these tools should be better automated, and that ultimately human intervention in the process is not going to be

Quality my favorite to use when showing friends for the quality and overall ease it's a high quality product, easy to use, and the web-sharing interface with measuring tools is super convenient

this is probably where we're going to spend a lot more time.... and it's open source, so that's awesome

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