Quality assessment of digital material has been just one of the new tasks the digital revolution brought into the library domain. With the first big print material digitization efforts in the digital heritage domain dating back to the 1980ies, plenty of experience has been gathered and recommendations on best-practise published. Along the same line, libraries of today may often publish guidelines on formats or quality parameters for digital textual materials which enter their holdings. While digital texts such as e-journals are in common use today, non-textual materials of various domains are just entering the holdings of cultural heritage institutions. An example for this is architectural data, which is of interest to a variety of libraries and archives – ranging from special collection libraries, such as the RIBA Library of the Royal Institute of British Architects, to national archives responsible for the archival of information about publically funded buildings. Architectural practise of today commonly includes 3D object processing. The output of these processes is slowly reaching the aforementioned cultural heritage institutions which are now facing the task of quality assessment of the material. The presentation will present a first analysis of potential quality factors and compare architectural and cultural heritage domain expectations in 3D data quality. It will look at two forms of 3D data: modelled 3D objects and scanned 3D objects. The work presented in this presentation is based on work conducted in the ongoing EU FP-7 DURAARK project.

1. Quality criteria for architectural 3D data in usage and
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preservation processes
QQML 2014
Istanbul, May 27th – 30th 2014
Michelle Lindlar (LUH / TIB)
Martin Tamke, Morten Myrup Jensen, Henrik Leander Evers (CITA)

2. Brief introduction to DURAARK
• to 3D scans
• to 3D plans(BIM)
Brief introduction to
digital preservation
Quality factors
• A digital preservation view
• A 3D plan / BIM view
• A 3D scanview
• A stakeholder view
Conclusion and Outlook
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Overview

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4. DURAARK (DURAble Architectural Knowledge)
FP7 – ICT – Digital Preservation (STReP)
February 2013 – January 2016
Goal
Develop methods and tools for digital preservation
and curation of 3D building data,
metadata, related knowledge & web data
Scope
• interlinked curation and preservation workflows
• focus on two open file formats:
IFC and E57
• incorporate existing OAIS compliant
digital preservation system
Project overview
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5. DURAARK – an interdisciplinary project
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6. ScanCoptor by FaroLabs
3D building data – scans
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Zebedee by CSIRO
Point clouds (E57 – ASTM E2907-11 Standard)
Point clouds are a set of points in a 3D (X, Y, Z)
coordinate system which describe the external
surfaces of a scanned object.
They document a building or structure „as-is“ /
„descriptive representations“ and are inevitably
tied to temporal and spatial aspects.
http://archive.cyark.org/exterior-cathedral-of-beauvais-3dviewer

7. 3D building data – models / plans
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Building Information
Modelling (BIM) (IFC – ISO16739:2013, based on STEP standards
ISO 10303)
Moves beyond CAD by covering the entire design-to-construction
process (including: project planning, cost, part
specifications, construction time, …). They traditionally
document a building or structure „as-planned“ / „perscriptive
representations“ which may deviate from the as-is state 
move towards „as-is“ state for facility maintenance.
3D CAD
Geometry along X-Y-Z axes
4D CAD
Schedule time
5D CAD
Cost-related information
6D CAD
Energy and sustainability
7D CAD
Facility management

8. 3D building data – models / plans
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9. Design-to-Construction-to-Retrofit Model
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10. Design-to-Construction-to-Retrofit Model
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11. 3D scans and plans are the research
output of respective
departments and will be found in
future legacy deposits of
architects and engineers /
current institutional repositories
BIM is already mandatory in several
countries for (some) publically
funded buildings, including
Denmark, Finland, Hong
Kong, Netherlands, Norway,
Singapore, UK, USA. Out of those
countries all but Hong Kong
require IFC for BIM
Cultural heritage organizations are
already scanning (and also
planning) cultural heritage sites
for documentation http://archive.cyark.org/exterior-cathedral-of-beauvais-3dviewer
Why should libraries and archives care ?
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12. The 3 [preservation] layers of a digital object
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13. Digital Object Lifecycle Model
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Based on DCC Digital Curation Lifecycle Model

14. What does „high quality“ of an object (typically) mean ?
From a digital preservation point of view:
To preserve an object at the quality needed to fulfill the future usage scenarios
of the stakeholder(s) – i.e., renderability, accessibility, understandability and
authenticity of the digital object.
From a user point of view:
To use an object in a way that all current needs are fulfilled.
What does ”high quality” mean ?
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15. Disclosure
well documented and openly available specification, stable versioning
Internal characteristics
free from encryption and DRM, complexity adequate for intended use
External characteristics
independent of hardware, physical medium, specific software / OS, external
information
Format acceptance
support through different vendors / available tools,
used by several domains, standardized
Patent
free from patent / licensing costs
Logical Strucuture / Transparency
Self-documented format, standard or simple representation of
data at logical structure, transparent to „simple“ tools
Quality criteria for digital preservation:
File format sustainability factors
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16. Short defintion:
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Characteristics which need to be preserved over the course
of time / over preservation action.
„Environments“ can be hw,
sw, community,
institutional/organisational
characteristics – such as
rendering, editing, storage
cost.
Farquhar, Dappert (2009):
„Objects“ include
bitstream, representation
and intellectual entity
levels – characterisitics
can be page count,
resolution, font.
Quality criteria for digital preservation:
Significant Characteristics

17. Level of detail / Level of Development:
- indication how much detail is included in geometry /
model element
- how much each part of the geometry is developed
- e.g. CCS Informationsniveuaer or BIMForum Level
of Development
Level of Accuracy:
- indication whether plan (for existing building) is
accurate representation of as-is
- indication scale can reach from „created based on
manual measurements taken from analogue 2D plan“
to „created based on 3D scan“
- best practise: DTU (Danmarks Tekniske Universitet)
Level of self-containment:
- indiciation of external sources the object
is depending on (e.g., vendor databases) Level of development for plumbing fixtures
3D plans / BIM– possible quality descriptors
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taken from BIMForumLevel of Development

18. 3D scans – possible quality descriptors
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19. Scanning companies / land surveyors:
- high level of detail and accuracy in scans
- use detailed parameters to describe deviations (e.g. drift of registration,
amount of noise, point to scanner distance, etc.)
Architects and Engineers
- focus on lean and uncomplicated collaboration/data to the benefit of the client
- level of information should match the purpose
Construction companies
- exact and detailed information in plans necessary
(highest degree for BIM amongst stakeholders)
Faciliaty maintenance
- mid-level of detail required (to lesser
degree than construction companies)
- high focus on correct models
(long-term sustainability)
Stakeholder factors
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20. Findings
- first quality factors which can serve as
significant characteristics have been identified
- quality expectations differ greatly between the
stakeholder groups for architectural data
- long-term archives need processes to assess the
quality for the respective stakeholders
- first tool for E57 quality assessment has been
developed in DURAARK project
Outlook
- development of IFC quality assessment tool
is currently underway
- workshops to test tools and processes with
stakeholders will take place in the fall
Interested in further information?
Deliverables are available on the website
www.duraark.eu
Conclusion and outlook
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21. Thank you. Questions? Suggestions?
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Do you have architectural
3D data? Contact us!
www.duraark.eu
michelle.lindlar@tib.uni-hannover.de
martin.tamke@kadk.dk