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Copyright © 2007 Open Geospatial Consortium. All Rights Reserved
to specify a profile for that use case. Having the profile then means that implementations don’t waste effort on implementing features of the full spec that
are not going to be used. If the profile is built around implementation issues it could exclude part of the spec because it is difficult to implement despite the fact
that people need to use it. The result of this would be non-adoption of the standards since they do not fit the requirement. Profiling IFC to handle only
spaces and space usage is a good example of a profile – those elements of IFC were the ones relevant to the use case. We need a body of serious use cases and
experience to draw on to get the profile right – this is something for the long term. 7 Transactions on CityGML. This topic was addressed in OWS-4 only in terms of
the exchange of complete feature collections in IFC. The notion of maintaining topological and semantic integrity in a transactional server is much more
challenging. Perhaps specific views and profiles of BIM and CityGML could support insertions and deletions of content that could be considered self-integral.
Simple changes of attributes would be a start. Transactions hold many challenges for the future. Workflow protocols such as service chaining and Business Process
Execution Language BPEL may also hold out hope for handling long transactions and integrity checking necessary for dealing with feature-level editing
transactions.
4.2 WFS for BIM
There are not many implementations of transactional BIM servers in the world, and through their participation in OWS-4 Onuma Inc. proved that a couple of tweaks to the
classic WFS-T interface can provide BIM feature access to the geospatial community. A diagram and outline of the WFS-T for BIM workflow demonstrated by Onuma is given in
the appendix to this document. 1 Focused Application Schema: It should be noted here that one of the reasons that
this implementation was possible to do in the short time frame of OWS-4 is that the Onuma view on BIM is defined very specifically to serve the needs of space
planners i.e. space geometries associated with large amounts of adjustable data is defined very specifically to serve the needs of space planners. As such is it avoids
a great deal of the complexity that is possible to represent in IFC. The space planning view is well suited for translation to CityGML. Finally it should be
17 noted that however simple the geometric data requirements for space planning,
compared with the potential complexity of BIM, this is perhaps the most valuable application from the perspective of broad-scale analysis. This is an important
lesson for future extensions of this BIM server functionality: It is very useful to focus on a very specific and limited application view as opposed to trying to
conquer the entire problem of transactional BIM services. 2 Metadata Catalog Concerns: As mentioned in the WFS discussion, above, there
will be a lot of value on exploring the sorts of identifiers that may be imbedded in IFC or otherwise attached to BIM feature collections that will facilitate their
registry and discovery through catalog interfaces. One issue related to this would be the means of publishing specific feature types or profiles that are available on a
server. Since these data don’t exist as GML until they are requested, somehow their definition will have to be imbedded in or independent of the BIM feature
store. 3 On-The-Fly BIM-GML Conversion: Our prototype focused exchanging
information about rooms IFC Spaces. The Onuma BIM Server stores these objects in an internal BIM format that incorporates the space attributer
characteristics of the US General Serviced BIM Guide for Space Assessment. The BIM server is capable of retrieving space objects with these attributes either
in CityGML or IFC format.
4 Transactions on BIM: These issues are similar to those discussed in the previous discussion on transactions on CityGML. It is perhaps more difficult because BIM
and IFC and their transactions are potentially much more complicated than CityGML. Nevertheless, there is a large need to solve this problem. The OGC
work on Digital Rights Management protocols will undoubtedly be very helpful in the development of transactional services that allow editing of selected BIM
objects.
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Copyright © 2007 Open Geospatial Consortium. All Rights Reserved
Figure 3: Web Feature Service for BIM
4.3 CAD BIM Editors and Analytical Tools
