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Research for the future: geometry analyses

Comparing geometry and finding exactly equal doors in a merged IFC model.

Although most of the BIMserver contributors are working to get the 1.0 stable release out to you, some users think its time to build for the future. For example Pim from the Netherlands organisation for applied scientific research TNO did some testing on comparing IFC geometry. As you might know, the merging feature in the BIMserver software is comparing IFC GUIDs to find equal objects in different sub-models. However, when objects are exactly the same but have different GUIDs (for example because of import/export problems with client side BIM editing software) the objects live a double life in the BIM model. Using brilliant geometrical analyses on the rendered IFC model Pim’s software was able to find geometrically exactly overlapping objects. In the example (picture) Pim found exactly overlapping doors (with different GUIDs). This could be a new feature in the merging function of the open source BIMserver. Tell us if you like this feature, or if you think that these kind of analyses don’t belong in a BIMserver, but should be done by client side analyses software tools.

Linking BIM and GIS

The world of BIM is getting more and more about buildings in a surrounding instead of just one building. The world of GIS is getting more and more about 3D objects and making the breach above the surface. These two worlds are getting closer to each other. The first part where these two worlds meet is CityGML. CityGML is an initiative to store semantic information about cities. The information is about buildings, but also surrounding (roads, etc) and geographic information is stored in the same standard.
The information about buildings in CityGML is very basic. Because at a city-level only the envelope of a building is interesting, there is no possibility to store information about floors, innerwalls, and other information about the inside of a building.
Luckily however CityGML gives developers the possibility to extent the standard with a specific Application Domain Extension (ADE).  BIMserver.org is developing a ADE for BIM information in CityGML. This development isn’t done in a day. We are working on it for quit some time now and it won’t be done overnight. Most important part is the transformation of the geometry. We are using the IFCEngine DLL from TNO to transform the semantic geometry of IFC to explicit geometry of GML.
The first results of this transformation are captured in a screenshot which we don’t want to keep for ourselves.
What you see is an IFC model in the free IFCbrowser (top) and the same model, transformed by the BIMserver software to CityGML in the FZKviewer.
Remember: still a long way to go….
The world of BIM is getting more and more about buildings in a surrounding instead of just one building. The world of GIS is getting more and more about 3D objects and making the breach above the surface. These two worlds are getting closer to each other. The first part where these two worlds meet is CityGML. CityGML is an initiative to store semantic information about cities. The information is about buildings, but also surrounding (roads, etc) and geographic information is stored in the same standard.

The information about buildings in CityGML is very basic. Because at a city-level only the envelope of a building is interesting, there is no possibility to store information about floors, innerwalls, and other information about the inside of a building.

Luckily however CityGML gives developers the possibility to extent the standard with a specific Application Domain Extension (ADE).  BIMserver.org is developing a ADE for BIM information in CityGML. This development isn’t done in a day. We are working on it for quit some time now and it won’t be done overnight. Most important part is the transformation of the geometry. We are using the IFCEngine DLL from TNO to transform the semantic geometry of IFC to explicit geometry of GML.

The first results of this transformation are captured in a screenshot which we don’t want to keep for ourselves.

What you see is an IFC model in the free IFCbrowser (top) and the same model, transformed by the BIMserver software to CityGML in the FZKviewer.

Remember: still a long way to go….!