When federating multiple models from different designers, it is not uncommon, that displaying them simultaneously in Dalux will result in a vertical offset due to inconsistent elevations in the model files.
Infrastructure projects have the additional challenge of being modeled in their exact coordinates. This can lead to offsets in latitude and longitude if not done correctly.
This article addresses possible reasons why models are not shown as expected and how to address changes for a correct result.
Finding elevation offsets
In addition to the visual offset in the Dalux BIM viewer, you can also use the viewer to investigate the reason behind it. To do this, go to
Locations
Open the building in 3D
Measure
Position marker.
Select points in the models for which you know the supposed z-coordinate. The position marker shows their coordinates, from which you can deduct which model is not placed correctly.
Alternatively, if you are using IFC files, you can investigate the models outside of Dalux as well. This is helpful if the distance between models is so big, that Dalux does not visualize them together anymore.
To do this, find the IFC file on your computer and open it in any text editor of your choosing.
Geometries are placed in a 3D space with a combination of their own coordinates and the reference point of the model.
Find the coordinates of a geometry, by finding the geometry (e.g. via its ID) and follow the references to the points that make up the geometry. The third parameter of this attribute will have its z-coordinate.
The reference point is most commonly defined in the attribute IFCSITE, which will carry the elevation as the third last parameter.
Add these two values to see where the geometry is placed in Dalux and validate this with where it should be placed according to your project requirements.
Changing the model elevation
Most commonly, elevation differences are a result of different approaches to setting the coordinates of a building. While one engineer adjusts the survey point, the other includes the offset in the geometries themselves. Combined with different exporting processes, this can lead to an incorrect offset in Dalux.
WARNING
Be aware, that any changes to the models should be made by the original designers. If you are not the designer and make changes yourself, you are imprinted as the author of the file, thus giving you the responsibility for its data.
We recommend using the same software in which the file was originally created. Depending on the export settings, different reference points can be used to place the model. Their respective support material helps you set this reference point correctly.
If you use the Revit plugin, the survey point is used to place the model in the correct position. You can use this guide to adjust the survey point: Revit Survey Point.
If your models are still not displayed correctly, please reach out to our technical support team.
Changing placement in infrastructure projects
When using InfraField, Dalux places models automatically in a selected coordinate system which you can choose. If your model is not displayed correctly on the map, it was probably exported or modeled in the wrong coordinate system.
Similarly to buildings, you can find information about their coordinates either with the Position marker or by investigating IFC attributes. Common reasons for incorrect placement on the map are:
-
Selection of wrong coordinate system: Some coordinate systems are similar with only minor differences. Make sure you have selected the correct one by using the correct EPSG code.
- Wrong coordinate system in the model: It might be possible, that engineers chose the wrong coordinate system in the modeling software. This should be corrected in the original software.
- Additional offset: It might be possible, that engineers added an offset to their model that was not respected in the export. Get in touch with your design teams to check if this is the case.
If your models are still not displayed correctly, get in touch with our technical support team.