The technique involves querying the drawing database programmatically using the LISP programming language and extracting the bounding box coordinates for all the 3DSOLID entities found, and then writing these data to a text file as properly formatted &OBST lines for FDS. However, a technique has been used successfully in the Autodesk’s AutoCAD environment to extract the coordinates of 3DSOLID entities directly. The properties of 3DSOLID objects are often not easily accessible due to the proprietary nature of CAD systems. In order to share the DXF file of a building model constructed with 3DSOLID, a separate conversion process would be necessary. Current commercial CAD applications offer 3D solid modelling as a more efficient method for constructing building models. To use this utility, a building model must be constructed entirely of 3DFACE objects, which are not widely supported. For FDS, a software utility DXF2FDS developed by Sheppard can be used to extract 3DFACE entities from DXF files created by CAD applications and generates FDS version 4 compatible obstruction block data. The building geometry information required by FDS as input is quite different to those required by zone model applications and these differences are discussed elsewhere.

The ability to share a common building information model between design and engineering analysis software applications depends on how successfully the data can be mapped from one schema to the other. is assumed that readers are familiar with zone and field modelling concepts and also with computer fire simulation tools such as BRANZFIRE and FDS.

Fds pyrosim