Being able to treat building components as standardised objects will allow them to be downloaded from manufacturers' websites into CAD systems. Before this promise has had time to unfold, the next step in objects is taking shape - having standards for enough of building description in 3D CAD to feed this object description data automatically into simulation programs.
Last week's column mentioned some of the infrastructure for this. The XML computer language succeeding HTML to allow CAD data to be processed not just displayed as pictures (of text and images) on the Web. That is half the story. To process the data we need to complement XML's data structures with standards for building data description, called schemas. With schemas in place, different computer systems can share the same data - known as interoperability.
Earlier this month US software firm GeoPraxis launched a schema called Green Building XML (www. ideaserver. com/gbxml. htm). This allows building data from CAD to be fed automatically into environmental simulation programs. The first implementation runs with a US CAD system, the user-unfriendly DOE-2 simulation software and an interface to that which is also from GeoPraxis.
GeoPraxis is now offering its Green Building XML schema to the standardssetting body, the International Alliance for Interoperability, as a potential open standard. If adopted and then implemented by vendors of CAD and simulation software, any simulation program could take data from any CAD program and run simulations.
Future schemas could allow simulation of any building performance, cost, buildability, whatever. This might require a more complete 3D model than otherwise needed. But the potential for such ready simulation again supports the use of a shared 3D project model.