BIM (Building Information Modelling) is a process of creating an information model of a building or other structure. The model (project) based on this technology is the basis of designing, constructing and later management of a building or structure. In addition to 3D-model the BIM-technology model uses a fourth (time) and a fifth (money) and if necessary a sixth (managing information) dimension. When creating an information model we will draw a virtual 3D model, that gives the Client an early idea of the building or structure, of the time needed to build it, of the cost and later managing costs. It offers the Client an opportunity to make necessary changes or find alternative solutions already during the designing process. For the builder it gives an opportunity to carry out the construction works according to a very specific desing, where all the junctions and structural elements are separately and easily viewed and calculated.
The basis of using BIM-technology is substantial and accurate 3D source information. Acquiring such information using traditional 3D surveying has been so far a time-consuming and costly process. This is were the modern laser-scanners come into play. These scanners are capable of emitting up to a million pulses per second and can survey the chosen area (e.g. a stretch of road) in a very short time. The result is a dot-cloud consisting of a lot of coordinates and thus gives us a very thorough overview of the area. By connecting the dot-clouds of several surveying stations we get a dot-cloud model of the whole site, which will be the basis of creating the BIM-technology information model of a building or structure.