BIM stands for Building Information Model/Modeling. BIM is known for including a lot of information on every object in a model.

Every object – what does it mean?

First, data is handled mainly in the ifc format (Industy Foundation Classes) which is a de facto industry standard. Ifc only contains objects which are solids or 3D-spaces. In other words, no points, lines nor polygons that we usually see in a map. It means that objects are solids or possibly spaces. This provides us with a three-dimensional model and information which creates a possibility for a fourth dimension, perhaps even a fifth dimension like time and cost.

Topocad and BIM – import and export

Topocad imports both the ifc-format and the City-GML which also maintains BIM data. The format is read and creates solids or spaces in the Topocad drawing. Metadata, the information, stays on the object. The export is made to the same format, ifc and City-GML, and metadata is created with help from attributes which is then connected to the file. This data is both global for the file and unique for each object.

Something that every object needs is a ‘type’. Type is for example slab, wall, window, column, beam, surface, pile, pipe and so on. Unfortunately, the regalement for infrastructure model data is not done yet, so an asphalt becomes something different, like a slab or a surface.

Stake out from a BIM-model

In this area there is plenty to develop, both in applications (mainly field computers) but also as a creator of data, for designers who handles BIM-models. In Topocad we have made automatic functions to create polylines out of wire frame lines in solids. Of course, you will be able to export these polylines into the field computers. It is also possible to draw points on all kinds of solids with the snapping command. There are no roadline data in a solid and it can be hard to find the middle of a cylinder. These are things which the designer needs to compliment in the design of the model.

Volume calculation using BIM

BIM is the same as solids, and solids are the same as volumes. Therefore, BIM is of course cut out for volume calculation! In Topocad, solids are used as a graphically result in a couple of calculations. For example, a cross sectioning always creates solids. A new function in 18.1 is to use slopes between terrain models directly. In Topocad 18, there was a new way to calculate volumes for civil properties with different layers, such as wear layers, bearings, fibre cloth, reinforcement layers, and just by clicking on the surface, solids are created. Finally, we create lots of volumes easily by using solid macros where you quickly create volumes and lengths by clicking on objects.

Surveying with BIM

In Topocad we solve this by using calculation functions in the code table. It even makes it easier to measure more with solids than to measure a regular polyline. Select both materials and a product code (for example AMA or CoClass) in the calculation function. We have created calculation features for pipes, pillars, piles, curbs and all types of longitudinal profiles, surfaces and cylinders. For Topocad version 18.2, we develop special features to easily measure houses as solids according to LoD 1 and LoD 2, and according to the Swedish Geoprocess standard.

Next phase within BIM

The next phase within BIM is called iBIM, ie an information model common to all parties involved with access to it via a server. It’s not really until then that BIM will be really good. Adtollos TC5D is a step towards this.