Prototyp - CVM

CAB - München. The coordination of information between different designers is daily work during the building design process. This work can be made more effective if it would be possible to use CAD files from each other. Prerequisites for this are on one hand a powerful data exchange format and, on the other hand, common structures for layers and attributes for CAD files.

A common layer and attribute structure is a step towards "integration by communication" with a proven existing technique. With a common layer and attribute structure a higher level in respect to the quality and time of the design and construction processes is reached, because there is greater data consistency and an application-independent data exchange.

The COMBI Visualisation Manager (CVM) is an integrating module for application tools, which is based on the concept of a harmonised layer and attribute structure (LAS). Through CVM the visualisation of geometrical data contained in any application system is realised in a consistent way.

CVM is a prototype software system that provides a way to visualise product data generated by the COMBI application tools by means of a CAD file which is structured according to the established Layer and Attribute Structure.

The Layer and Attribute Structure itself is developed in view of the requirements of the COMBI application tools and the COMBI Object-Oriented Product Model, as well as in view of existing layer and attribute structures and the functionality of traditional CAD systems.

The data exchange with the application tools is based on application models formulated in the EXPRESS language (ISO 10303-11). The exchange files have the related physical file format ISO 10303-21. CVM creates output CAD files out of the geometric descriptions of the design objects contained in the application models. These output CAD files are analogous to the STEP Application Protocol "Explicit Draughting" (ISO 10303-201) and are structured in accordance with the COMBI Layer and Attribute Structure. They can be imported into any CAD system capable of reading STEP AP 201 files.

The main step in CVM is the mapping of the output data from an application tool to an appropriate CAD representation, using a formal mapping language. The mapping not only of geometrical data but also of related non geometrical attributes is taken in consideration.

For the prototype implementation existing tools have been used as much as possible.