Abstract
Layering is a widely used method for structuring data in CAD-models.
During the last few years national standardisation organisations,
professional associations, user groups for particular CAD-systems,
individual companies etc. have issued numerous standards and guidelines
for the naming and structuring of layers in building design. In order to
increase the integration of CAD data in the industry as a whole ISO
recently decided to define an international standard for layer usage.
The resulting standard proposal, ISO 13567, is a rather complex
framework standard which strives to be more of a union than the least
common denominator of the capabilities of existing guidelines.
A number of principles have been followed in the design of the proposal.
The first one is the separation of the conceptual organisation of
information (semantics) from the way this information is coded (syntax).
The second one is orthogonality - the fact that many ways of
classifying information are independent of each other and can be applied
in combinations. The third overriding principle is the reuse of
existing national or international standards whenever appropriate. The
fourth principle allows users to apply well-defined subsets of the
overall superset of possible layernames.
This article describes the semantic organisation of the standard
proposal as well as its default syntax. Important information categories
deal with the party responsible for the information, the type of
building element shown, whether a layer contains the direct graphical
description of a building part or additional information needed in an
output drawing etc. Non-mandatory information categories facilitate the
structuring of information in rebuilding projects, use of layers for
spatial grouping in large multi-storey projects, and storing multiple
representations intended for different drawing scales in the same model.
Pilot testing of ISO 13567 is currently being carried out in a number of
countries which have been involved in the definition of the standard.
In the article two implementations, which have been carried out
independently in Sweden and Finland, are described.
The article concludes with a discussion of the benefits and possible
drawbacks of the standard. Incremental development within the industry,
(where ”best practice” can become ”common practice” via a standard such
as ISO 13567), is contrasted with the more idealistic scenario of
building product models. The relationship between CAD-layering, document
management product modelling and building element classification is
also discussed.
Original language | English |
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Pages (from-to) | 32-55 |
Journal | Journal of information technology in construction |
Volume | 2 |
Issue number | 2 |
Publication status | Published - 1997 |
MoE publication type | A1 Journal article-refereed |