||It all started twenty years ago with the implementation of industrial and mechanicalCAD-drawing systems in the Construction Industry. Even at that time we focusedon the wonderful perspectives of integrating design, production processes and FMusing integrated systems, based on a "digital building model" and "object orientedmodelling".The vision and the goals for the use of IT in the Construction Industry have beenextremely stable over the years - much more stable than the development of IT.For many practical reasons we started out by focusing on drawings and onbuilding bridges between the "islands of automation" in the construction industry.Data exchange between CAD-systems was on the agendas for some years. But whyare we still fighting the challenges of file-exchange between loosely coupledsystems, and why do we still base industrial practices on the document managementconcept, when comparable industries have left this concept long ago?We thought, that the concept of file-exchange between loosely coupled systemswould bring us closer to realising our final goals - but how far have weprogressed? Are we closer to integrated modelling today? How far have weprogressed when it comes to implementation in the industry?The author takes a close look at the development and the use of IT in practice in theDanish Construction Industry and in numerous development programmes. Hesummarises on the lessons learnt in different areas like: Industrial IT- strategy, ITandCAD-solutions, conditions for integration, workflow, collaboration andbusiness culture in the Construction Industry. He relates to the development inother industrial areas and to the development of IT-systems and tools to support theconcept of integrated modelling and points at development needs.The author elaborates on the ideas of information modelling in 1D-, 2D-, 3D-,4D-,and up to 8D (?), dealing with three dimensions, properties, relations, space, placeand time, and asks the question, if we have to go through all these steps to reachour goal.The conclusion is, that the industry is facing a shift in paradigm in order to fulfil itsgoals on integrated modelling, and that there is no easy way. The more we focus onfile-exchange between loosely coupled systems and on the document managementconcept the further we must travel, and the greater the risk, that we will neverreach our goal.