Working with CAD data – Exporting site models for CAD

Scalgo Live can export convenient site models that can imported into CAD software for further design and analysis.  

The site models contains the terrain, buildings, and some land cover classes (where available). They are translated into layers and objects that can be utilized in the CAD software:

• Buildings
  Exported as blocks with a fixed height of approximately 10 meters.

• Trees (Revit-specific)
  When targeting Revit, a dedicated trees layer is included.

  • This layer contains points sampled from dense vegetation areas.

  • The default sampling density is set at ~30 m² per tree.

• Other land cover classes
  All remaining classes (e.g., paved roads, unpaved roads, water) are exported as separate layers, making it possible to assign materials or properties once imported into AutoCAD, Civil 3D, or Revit. More information about land cover classes.

By the way, you can also import CAD data into Scalgo Live.

Scalgo Live offers site models optimized for major CAD software environments - you select the software you are targeting in the first step:

• In AutoCAD format, the terrain is stored as a triangulated mesh, there are 3D models for buildings, and polygons for roads and water bodies. More details.
• In Civil3D format, the terrain is stored as a
  triangulated mesh, there are 3D models for buildings, and polygons for
  roads and water bodies. More details.
• The Revit format is optimized for creating a toposolid in Revit. You can subdivide the toposolid to show roads and water. More details.
• The Rhino format is needed for Rhino3D, which cannot handle native GIS coordinates - all coordinates are shifted to be centered around zero. It is otherwise identical to the AutoCAD format. More details.
• In the Generic format, you receive separate triangulated meshes for roads, water, and the rest of the terrain. This allows to quickly visualize a 3D scene in any CAD software that can read DWG files. More details.

1. Select the export in the toolbar and then select  Site plan (CAD) in the dropdown.
2. Select the CAD software you are targeting.
3. Select the area you want to download:
   
   • you can select a simple rectangle
   • draw an arbitrary polygon
   • or drag a polygon (shape or geojson format) directly into your window.
4. Single-click to start drawing an arbitrary polygon.
5. Single-click to add new vertices.
6. Double-click to stop drawing.
7. If your area lies inside one of your workspaces, then you can now decide if you want to use the national layers (the most recent terrain, buildings, and land cover), or if you want to export data directly from your workspace.
8. Finally, you have a choice of projection and can adjust the precision of the mesh being produced.

When creating the site model, we simplify the detailed elevation data from Scalgo Live to generate a file that your CAD software can handle efficiently. The precision parameter controls this simplification process by defining how much the simplified mesh in your site model may deviate from the detailed elevation model in Scalgo Live.

A higher precision value allows greater deviation, resulting in a smaller file with fewer mesh vertices. Conversely, a lower precision value restricts deviation, producing a more detailed mesh but a larger file.

Scalgo Live also supports the export of flooded areas. The output is a set of polygons, which the users can then use to visualize the extent of flooded areas in CAD software.

You can follow the regular process for downloading flood extent polygons from the Flash Flood Map. Here are the steps:

• Go to Export ➤ Download data.

• Select the desired area.

• Choose Flash Flood Mapping ➤ Flooded Areas ➤ Polygon ➤ Extent polygons.

• Select Vector format ➤ DWG (dwg).

Import the exported flooded areas DWG as a separate file into Revit.

• Add a sub-division for this layer according to the Revit CAD import workflow (8. Add subdivisions).

• Remember to include all other sub-divided classes before the Flooded Areas.

• Assign a sub-division height that is a few centimeters above the predefined height to improve visualization.

You can try to import the exported flooded areas DWG as a separate file using Copy to Original coordinates or add it as XREF.

Note that this layer is set to Z = 0 elevation, which can be used for layout or site plans only.