There is significant scope for increasing the performance of commercial buildings across all dimensions of sustainability. For this to be realised, however, requires the development of more advanced real time assessment systems which provide automated eco-efficiency performance checking direct from 3D CAD as a regular and integral part of the design process rather than in late or post-design where options are more restricted. An integrated approach to directly link choice of materials and their environmental impacts with 3D CAD model object-oriented files containing significant building information, has been developed by the Cooperative Research Centre for Construction Innovation as a first step in this process. From 3D CAD objects, the system called LCADesign* automatically obtains the quantities of all building components associated with the selected products, calculates a complete inventory of constituents of building products, and links these to a Life Cycle Inventory database of building materials. The Life Cycle Inventory database includes all resource usage and emissions to the environment from the extraction of raw material resources, through their manufacture, transport, use, recycling, and maintenance. A number of performance assessment indicators can then be used to compare options in the choice of materials or design. An application to a commercial building project in Melbourne, Australia is provided to illustrate the potential of virtual building modelling.