3D models will almost always need to be accompanied by some supporting information. Important information to include:

• Overview: A title for the model and enough information to know what to expect.
• Orientation. Which way is up? Where is the front?
• Scale. Is the model to scale? If not, what is the scale? It can help to provide a reference line to indicate the relative size of a person, ant or other relevant object with a well-known size.
• Important features

Much of this information can and should be provided by a teacher, classroom aide or museum/gallery guide. However, labelling is still important to enable independent exploration.

Quick links: Print labels; Braille labels; Basement; 3D symbols or icons; Audio labels; Return to the 3D printing guidelines overview.

Overview of methods for labelling 3D prints for accessibility

The following table gives an overview of the methods and technologies available for labelling 3D prints. Follow the links for further information on this page.

Labelling method	Minimum size	Additional requirements	Pros and cons
Basement	Must be larger than the 3D model	Tactile graphic	Can give detailed information about specific parts of the model. Also assists with orientation of the model.
Braille label	0.64cm high × variable width	None	Information is given on the model without the need for external systems or a key. Not suitable for complex models. User must know braille.
Braille symbol (22-3 cells)	0.64cm high × 1.24cm wide	Key	Can give detailed information about specific parts of the model. Can be confusing if orientation (which way up) is not clear. User must know braille.
UBIS symbol	1.65cm high × 1.6cm wide	Key	Also indicates which way is up. Quite large.
3D symbol or icon	variable	Key	Can be intuitive, reducing the need to refer to the key.
QR code	2.5 × 2.5cm minimum; 3 × 3cm for 1,000 characters or more	QR code reader on phone or tablet	Can provide a large amount of text or other other media. Free, using mainstream technology. Quite large.
Passive RFID tag	Variable	RFID reader	Limited to one label per model. Needs special equipment.
NFC tag	25-38mm2	Smartphone (iPhone 6 or higher; many newer Android phones)	Limited to one label per model. Needs special equipment.
Penfriend (or similar)	Variable	Penfriend device and labels. Tactile indicator around the label.	Easy to use. Uses an individual device (not distributable). Expensive.
Touch triggered electronics	Variable	Conductive material, microcontroller board, speaker or headphones, and power source.	Familiar touch based interaction (e.g. single-tap & double-tap). Creation requires expertise. Relatively expensive.

Print labels

The addition of print labels makes an accessible tactile model inclusive, so that it can be used together by people with any level of vision.

Small print labels should be added using thin indents, as these are not obvious by touch and will not interfere with touch reading. If placing print and braille labels together, position the print label above the braille so that it can still be seen while fingers are touching the braille.
Add visual contrast to the print label by colouring inside the indented letters with a permanent marker or similar.

When space is available, large print letters can be added using raised lettering.

Braille labels

Braille labels provide an immediate way to recognise the title or parts of a 3D print by touch. They must be placed on a smooth surface and the user must be able to read braille. As braille requires a lot of space, only short braille labels can fit onto 3D models. If the orientation of the braille is not clearly evident, add a tactual indicator such as cutting off the top right corner of the label.

If possible, place braille labels at the front of a model as a tactile indication of which way it should face.

3D printed braille labels

As braille must be given at a standard size, do not incorporate braille labels on models that are likely to be printed at a variety of scales.

Braille labels can cause confusion when trying to interpret complex models and alternative methods for labelling should be used in these instances.

If using a FDM printer (most common), braille should be printed upright (at a 90% angle from the printing plate) to achieve optimal tactile quality and readability^{1, 2}. Models with flat surfaces on the side are ideal candidates for braille labels. If the braille needs to be placed on the top or base of a model, either print the whole model on its side or print the braille labels separately then insert them after printing.

It is possible to wrap braille on curved surfaces, however the process is time-consuming. A short braille symbol is advised with a key provided on an accompanying basement, braille page or electronic document.

A suggested process to place braille on curved surfaces:

1. Open the model file in Fusion 360.
2. Write the braille as text and import into Fusion 360 as an .svg file.
3. Make hemispheres for one complete braille cell, copy and paste across as needed, then delete the hemispheres that are not needed.

There are several options for generating 3D braille:

• Good quality braille on a flat surface, including contractions, can be custom created using the OpenSCAD file at www.thingiverse.com/thing:4167866. The resulting .stl file can then be incorporated with any model using your preferred software.
• https://touchsee.me/ is an online convertor from print text to braille labels, which can be used by people without any knowledge of braille. Note that Unified English (contracted) is not the default translation code and must be selected. The braille dots quality is good, however the base is very thin. A thicker base is needed to print the braille on its side.

Note that TinkerCAD now has a braille generator under the Shape Generators menu. It gives direct translation to uncontracted braille (not using ASCII). However, this option is NOT recommended because the braille is designed as flat columns.

Alternative methods to provide braille labels on 3D models

When braille labels are not suitable for any of the reasons above, sticky braille labels can be added onto the model after printing is complete. Clear adhesive glue may be needed for a strong bond on curved surfaces.

Consider adding sticky braille labels underneath a model with a flat base, such as a map.

Basement – a base plate or tactile graphic

A base plate with an outline or slot for the model will give an indication of orientation (which way up) and can include labelling. This is the recommended approach for complex models with substantial labelling requirements.

Alternatively, a tactile graphic can be created with a tactile outline for placement of the model (which way up and which way forward). This tactile graphic should include a title and can also include a written description, braille labels, a key and/or a QR code for further information.

3D symbols or icons

If the base model is sufficiently simple, 3D symbols or icons may be preferred over braille because they are scalable, they can be read regardless of orientation, and the touch reader does not need to know braille.

The European UBIS project recommended a V symbol with dots, which serves the dual purpose of indicating which way is up³. The 3D files for the V symbol can be downloaded from the tactiles.eu website. Always place the V pointing downwards and use the simplest symbols first. The measurements of the UBIS-V with dots are at least 16 mm width and 16.5 mm high.

Alternatively, it may be appropriate to design new tactile symbols (abstract) or icons (representational).

In order to be distinctive, icons should adhere to the following guidelines:

• Distinctive features should be located on the top – not on the sides or base, where they are less likely to be felt. For example, a cone can be felt more easily with the wide end at the base and the pointed tip at the top.
  
• The symbol or icon should be tactually distinct. For example, a plate with a knife and fork is not tactually distinct at a small size.
  
• The symbol or icon should be a unique shape that cannot easily be confused with other objects. For example, a hamburger could easily be confused with a bush or cushion.
  
• Icons should be representative of the concept you are wanting to convey so that they can be interpreted without ambiguity. For example, stairs can be instantly recognised.
  
  By contrast, a human figure is not a good icon on a general purpose map because it could be interpreted as representing “you are here”, “information/assistance” or “toilets”.
• Icons should be based on well-recognised symbols or objects that can be touched in real life. For example, the floppy disk icon to represent “save” is unlikely to be well known by touch readers, nor would it be tactually distinct.
  
• Simple shapes are best, without extra details that would require extra time for examination and recognition. For example, a bowl with chopsticks is quicker to identify than a bowl with chopsticks and noodles.
  

Audio labels

Audio labels are a good option when lengthy explanations are needed and the model will be explored independently. They also promote inclusion, as they can provide useful information to everyone, regardless of whether they have a print disability.

Penfriend and other audio label stickers

PenFriend, Anybook Reader and similar products provide small labels that can be added to objects and programmed with your chosen audio. To record labels using PenFriend, the tip of the pen is placed on the label, the record button is pressed, the user speaks into the microphone at the top of the PenFriend and presses the record button again once finished. The recording is stored and played back when the same PenFriend is placed on the label. The stickers vary in size and can be placed on components of a complex 3D model to provide annotations.

A selection of different devices are available from www.talkingproducts.com.
This is the easiest approach for creating multiple audio labels on a single 3D model, so that you can identify important parts. However, these systems are designed for personal use, with customised pairing between the label and the device. Cost begins at around $200.

QR codes

QR codes can be generated for free using sites such as QR code generator or QR code monkey, printed on standard paper or swell paper and stuck to the base of a model, at multiple points on a larger model, or on an accompanying basement. The user will then need to scan the code using a free app on any mobile device. If you have a lot of materials labelled with QR codes, the mobile device can be mounted on a stand so that the user does not need to hold it.

A tactile indicator, such as a raised outline or dots at the corners, must be given so that it is obvious where the QR code is located for easier scanning.

NFC tags

NFC tags are able to communicate wirelessly with smartphones at a distance of 10cm. Tags can be attached to the outside of the model or inserted inside the model during printing. The user will just need to tap their phone against the model. Because tags are read from 10cm away, only one NFC tag can be used per model, limiting their use to the provision of overall information about the whole model.

NFC tags work with iPhone 6 or higher and many newer android phones. NFC may need to be enabled in the phone’s settings.

Touch-triggered electronics

Audio trigger points connected to a microcontroller board can provide audio labels when the touch point is pressed. Microcontroller boards such as Bare Conductive boards (easy to set up) or Raspberry Pi (requiring more programming) can be connected to the trigger points with conductive material such as wires, conductive filament or conductive paint. Headphones or an external speaker are also required for the audio output.

This method of creating audio labels for 3D models is only recommended for high-use items. A moderate level of electronics and technical know-how is required to build the system, and controller boards begin at a cost of around AUD$70.

Last updated: June 3, 2024 at 12:16 pm