Working with CAD data – Importing from CAD

There are many ways in which you can bring data from your CAD software into Scalgo Live, just like vector data from other sources.

Scalgo Live supports reading and writing of the DWG file format, used by AutoCAD, Civil3D, and supported by many other vendors, and supports reading the DGN file format used by Microstation.  If you have a drawing or design in DWG or DGN format, you can use it in Scalgo Live in all places where data can be imported.

Temporarily visualizing CAD data

The easiest way to have a quick look at your CAD data in Scalgo Live is to drag a DWG/DGN file into the dock (the list of layers on the left side).   The data is then shown as an overlay on the map. 

Note that text annotations in your CAD drawing will actually be displayed as text in this overlay, making this an excellent way to quickly visualize a CAD drawing.

From CAD to Canvas

You can drag CAD data in DWG/DGN format directly into the canvas object list in the right sidebar.

Workspace edits from CAD

If you have drawn workspace edits in CAD software, you drag them into the workspace tool panel.  It's good to be aware of the slightly different behavior when dragging into the Select tool versus all the other tools:

In the Select tool, Scalgo Live asks you to provide a source for the various attributes of the feature, such as path width or elevation.  When your data was drawn in a 3D CAD software, you will most likely want to use "Value(s) from feature".

In all other tools, Scalgo Live sets the feature attributes to the values set in the tool panel, exactly as if you had drawn the same feature in Scalgo Live.  In other words, only the two-dimensional geometry will be used from your CAD file.

Importing a terrain model from CAD to Scalgo Live

When bringing a terrain model designed in CAD software into Scalgo Live, it is best to let the CAD software do the generation of the 3D model. This ensures that the model you analyze in Scalgo Live is really identical to what you are modeling in your CAD software.

The CAD software exports the terrain as a triangulated surface (TIN).  Two standard formats that are supported by Scalgo Live are LandXML and IFC.  Revit, for instance, supports IFC export directly.  

If the CAD software offers different levels of detail for the TIN export, we recommend setting this to high.  In particular in Revit the default setting of low for IFC export is sometimes not good enough - see here for details.

To bring your LandXML/IFC file into Scalgo Live, you can either create a new workspace with the "import" option, or import it into an existing workspace.

The LandXML/IFC file must use coordinates in meters in a known coordinate system (so you must know the EPSG number of the coordinate system). See the manual entry on Coordinate Systems for more information. 

In Revit, one can geo-reference the entire model, and then the IFC export is also properly geo-referenced, so that Scalgo Live can detect the coordinate system automatically. 

Scalgo Live reads the elevation of the terrain from the geometry in the LandXML/IFC file, so the z-coordinate should be the correct elevation.

What about the buildings on my terrain model?


When importing buildings, it depends a bit on what you want to achieve. You can simply export your entire CAD model as an IFC file. In that case, the geometry of the buildings would be part of the IFC geometry, and the buildings appear in Scalgo Live "baked" into the terrain model (so  the terrain goes up to the roof of the building) - quite similar to what it looks like in the national "Terrain/Buildings" layer you can see under "Elevation" in Scalgo Live. This is fine, for instance, for performing flash flood analysis on the workspace.

In some instances, however,  you want to import the buildings as "building objects", where Scalgo Live knows about them as actual, editable objects. This is necessary, for instance, when running DynamicFlood or for computing the wet part of building perimeters from the flash flood map.

To do that, you need to create a LandXML/IFC export of the terrain surface only, and export the buildings separately. To bring the buildings into Scalgo Live, you export them as 2D polygons (no z-coordinates are needed), for instance in DWG format. You can then drag this file into the "buildings" tool of the workspace.