The basic principles enabling a building product model to be used by the application programs of the different participants in the building process have been defined in an industry-wide cooperation project in Finland. The model is conceptual, using concepts such as objects, attributes, and different types of relations between objects. The model is capable of containing all kinds of data describing a particular building. In current practice, these data are contained in drawings, specifications, bills of quantities, etc. At present the model is not fully elaborated, but it will be further developed in subdiscipline-specific projects, as well as being tested by prototypes.