LONG-TERM PRESERVATION OF 3D ARCHITECTURAL BUILDING DATA: A LITERATURE REVIEWNOKOBIT 2013
Devinder ThapaMoutaz Haddara (presenter)Department of Computer Science, Electrical, and Space EngineeringLuleå University of Technology, Sweden
General introduction
Questions & methodology
Findings
Discussion
Agenda
2
Motivation
Long-term Digital Preservation (LDP)
• The series of managed activities necessary to ensure continued access to
digital information for as long as necessary.
• Involves the planning, resource allocation, and application of preservation
methods and technologies to ensure that digital information of continuing
value remains accessible and usable.
• It combines policies, strategies and actions to ensure access to
reformatted and born digital content regardless of the challenges of media
failure and technological change. The goal of digital preservation is the
accurate rendering of authenticated content over time.
http://en.wikipedia.org/wiki/Digital_preservation
LDP in a nutshell….
Sustainability Availability
LDP
LDP
metadata
ingestion
tools
storage
management
5
opennessschemas
data miningaccess
Example challenges of LDP
Digital decayDigital obsolescence
Example challenges of LDP
• Unlike traditional analog objects such as books, hand-drawn
architectural models, and photographs where the user has
unmediated access to the content, a digital object always needs a
software environment to render it. These environments keep
evolving and changing at a rapid pace, threatening the continuity
of access to the content.
• Physical storage media, data formats, hardware, and software all
become obsolete over time, posing significant threats to the
survival of the content.
Example challenges of LDP
• Huge amounts of digital data is created;
• Many levels interact (hardware, software, file formats, meta data
etc.);
• Lots of dependencies (HW & SW, operating systems, device drivers
and so on);
• Fast technical development and short life span (digital obsolescence);
• Metadata (technical, descriptive and administrative)
• Expensive (cost for storage media is only about 20% of the total
cost).
Big Data Dimensions (3Vs)
9Data Complexity
Volume
Variety Velocity
Some terms
• Building information modeling (BIM) is a process involving the generation
and management of digital representations of physical and functional
characteristics of a facility.
• Industry Foundation Classes (IFC) is a platform neutral, open file format
specification that is not controlled by a single vendor or group of vendors.
It is an object-based file format with a data model. IFC is an ISO Standard.
• Point cloud is a set of data points in some coordinate system. In a three-
dimensional coordinate system, these points are usually defined by X, Y,
and Z coordinates, and often are intended to represent the external
surface of an object. Used also in GIS systems.
Why 2D to 3D CAD Models?• Making 2D drawings is fast and easy, but does not readily work with downstream
systems like purchasing and manufacturing.
• Prototyping machines require 3D data.
• Viewing 3D cad models helps identify errors early. These errors can be found while
simulating the matching and mating of parts.
• Through the use of 3D cad, the assembly process of any given product can be
simulated, visualized and analyzed before the design goes into production.
• 3D cad models are essential beforehand in determining the volume of material
needed to mold specific parts as well. The use of 3d cad files also ensures that a
design has sufficient room for other parts within the design.
• Building state over time.
• Heritage preservation & building modifications (e.g. new insulations).
• The paradigm shift from 2D to 3D modelling;
• The access mechanisms of current preservation systems in the architectural domain are based on simple metadata schemas inherited from the analogue world;
• The absence of standard process and LDP strategies for 3D architectural data such as OAIS;
• DURARK.
Research Motivation
• Are the existing works on the preservation of object-based 3D architectural data complying with all the OAIS process?
• What are the challenges in various stages of the data ingestion by producers?
• How does the preservation of 3D architectural data differ from general digital preservation?
Research questions
Research Methodology
Table 1. The literature review process
OAIS(Archive)
Producer Consumer
Management
Adapted from Lavoie, Brian F. (2004).
Theoretical Framework -OAIS Environment
Theoretical Framework -OAIS Environment
• To standardize digital preservation practice and provide a set of
recommendations for preservation program implementation,
the Reference Model for an Open Archival Information System
(OAIS) was developed.
• OAIS is concerned with all technical aspects of a digital object’s
life cycle: ingest, archival storage, data management,
administration, access and preservation planning.
Theoretical Framework -OAIS Environment
• OAIS also addresses metadata issues and recommends that
five types of metadata be attached to a digital object:
• reference (identification) information,
• provenance (including preservation history),
• context,
• fixity (authenticity indicators),
• and representation (formatting, file structure, and what
"imparts meaning to an object’s bitstream").
SIP: Submission Information PackAIP: Archive Information PackDIP: Dissemination Information Pack
Theoretical Framework -OAIS
Findings
Ingest • Heterogeneous and inconsistent metadata schemas and ontologies• Lack of standard file formats• No vendor-independent solution exists yet, which would allow the
transparent, publically agreed storage of building-related concepts, properties, terminology and classifications
• The open IFC/IFD file formats representations of the 3D data can be used
Archival Storage • Original 3D model and the actual state of built architecture will vary• 3D point scanning can be one option
Data management • Need for concept repositories, dictionaries and meta-classification schemas for the uniform description of building products
Adminstration • Potential legal problems with 3D CAD licenses
Preservation Planning
• Lack an analysis in terms of OAIS preservation planning, particularly in terms of BIM and point clouds compression
Access • There is no OAIS compliant system that currently provides access with semantically enhanced 3D-objects, develop highly sustainable objects in regard to self-documentation and future reuse and searchability.
Findings
Discussion
• The largely fragmented nature of the industry and the large spectrum of
involved subdomains have led to heterogeneous and inconsistent
metadata schemas and ontologies for the description of building elements
and their properties in highly enriched BIM models. Without tackling this
problem, simple application of existing 3D long-term preservation
strategies is widely useless as it prohibits efficient data reuse in the future;
• The huge stock of legacy buildings that is represented either by by low-
level legacy 2D CAD models requires elaborated methods of
architecturally meaningful semantic enrichment, otherwise targeted
retrieval in the long-term archive is not possible;
Discussion
• Preservation planning as described in the OAIS model
must be investigated for the case of 3D point cloud
data regarding potential risks arising from the used
storage format which unavoidably must rely on some
compression techniques due to the sheer amount of
data.
DURAARK/Future research
DURAARK is expected to contribute to the following main functional OAIS entities:
• Ingest: DURAARK adds a domain specific quality assurance for the various data formats used
for architectural 3D. DURARK plans to build on the already operational PROBADO 3D system
as a first exemplary SIP producer.
• Archival Storage: Adequate compression techniques will be investigated regarding the
suitability for long-term archiving and eventually adopted.
• Preservation Planning: A sample preservation planning for 3D objects will be elaborated with
respect to the use-cases.
• Access: Depending on the designated community DURAARK will provide various components
to handle domain specific queries/requests and provide and convert the requested AIP into a
corresponding Dissemination Information Package (DIP). This includes formulating queries
e.g. searching for long-term archived data representing the state of a building.