LONG-TERM PRESERVATION OF 3D ARCHITECTURAL BUILDING DATA: A LITERATURE REVIEW

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

toolsstorage

management

5

opennessschemas

data miningaccess

Example challenges of LDP

Digital decayDigital obsolescence


• 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.


• 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


• 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.


• 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.

Thank you for your attentionQ&A

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