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Mass Customization of Respiratory Protective Equipment
mesh, forming the contact region between the mask and assembly and manufacturing instructions so that he/she
the user’s face, greater details can be found in Li et al. . can manufacture the mask at home (if a 3D printer is
[65]
These points together with the set of landmarks act as the available) or through commercial 3D printing services.
reference geometry in the CAD model generation step. This also served as a supply chain response to the global
In the previous study , Autodesk Fusion 360 mask shortage at that time, as the 3D printed mask could
[65]
API was employed. However, as it cannot be readily be used as a face covering or face shield.
integrated with the rest of the pipeline which was As facial scans are sensitive biometric data,
written in MATLAB, a Python based Blender script is Data Protection Impact Assessment has been carefully
now utilized to seamlessly interface the CAD API into conducted and approved by Imperial College London to
the pipeline such that the whole pipeline can run in a ensure all data-associated activities, including online data
headless mode. Blender builds polygonal 3D models collection, transfer, storage, and analyses, are secure and
from successive addition of vertices, edges, and faces compliant with relevant data protection regulations. The
through functions with defined rules and constraints. This study protocol (19IC5167) was approved by the Science
polygon-based generative geometric modeling approach Engineering Technology Research Ethics Committee,
can robustly handle the complexity and high variation Imperial College London.
of facial topographies, particularly around the nasal Eligible participants were adults (≥18 years)
regions, making it well suited to the requirements of a regardless of gender, ethnicity, or BMI. Before scanning,
MC pipeline for RPE. The design of the respirator mask participants were asked to read through a Participant
(Figure 2) remained the same with three standard Information Sheet to understand the project, how
[65]
components (grey) and a modifiable component (blue) their data will be utilized and to clarify any questions.
that will be updated geometrically in blender to achieve Written instructions were also provided on the online
[68]
custom-fit. portal to instruct participants to prepare for scanning
by doing the followings: clean shave their face, remove
2.2. Participants any glasses, and pin/tie all hair if it is obstructing the
[68]
Participants were recruited from mid-July 2020 to mid- face. Video instructions were provided to ensure that
October 2020. Due to travel restrictions during the facial data were acquired under the same conditions.
COVID-19 pandemic, a dedicated online portal was Participants were recommended to use an iPhone X or
[66]
created to collect 3D facial scans remotely. This way newer versions (Apple Inc., Cupertino, California, USA)
of data collection transcends geographical boundaries, with a TrueDepth camera to acquire their facial scans.
thereby enabling us to reach a wider demographics. However, facial scans obtained from other acquisition
Recruitment was advertised on mainstream media devices were also accepted. If an iPhone was used,
platforms such as the BBC , as well as on various software applications recommended for creating and
[67]
social media platforms. As a token of appreciation to exporting 3D facial scans were ScandyPro (Scandy,
each participant, a custom-fitted mask model generated New Orleans, USA) and Bellus3D (Bellus3D, Campbell,
from the pipeline was emailed to the participant with California, USA). Participants were also instructed to
remain in a neutral expression during the data acquisition
process. Once a scan had been acquired, participants
were instructed to upload their scans through the online
portal. Demographic information including age, gender,
ethnicity, weight, and height were collected through a
short survey in the submission process. Before the final
submission, permission was sought from each participant
to use their data anonymously through an Adult Consent
Form. Details of the survey and consent form can be
found in the online portal .
[69]
2.3. Scan exclusion
Facial data acquisition is not a trivial task and will
require the user to have a good level of understanding
of the acquisition device and software to obtain 3D
facial data with minimal noise and obstruction. While
written and video instructions were provided to guide the
Figure 2. Custom-fitted mask body generated using Blender with participants on data acquisition, it cannot be assumed that
standard FFP3 filter components. all participants have followed the instructions diligently

126 International Journal of Bioprinting (2021)–Volume 7, Issue 4