To import terrain

Import raster-based data (grids) or vector-based data (TIN or contour files) as terrain. Terrain represents the land upon which the model is built. Other data is draped on the terrain.

Note: The steps below describe how to import terrain data from sources of your choice. If you use the Model Builder to create a new model's base layers, it imports and configures terrain data for you for the area of interest you specify.

Autodesk InfraWorks 360 supports many formats listed on http://www.gdal.org/frmt_various.html, as well as LandXML. See About Exchanging Data with AutoCAD Civil 3D to read how InfraWorks handles bringing data into a model from AutoCAD Civil 3D.

1. Follow the general import instructions.

   Specify a file representing contour information or a raster file.

2. Click Data Source Configuration > Source tab and set Draping Options to Don't Drape.

   Any other setting would cause other data to be inaccurate.

3. If you are importing a raster file, you can clip the imported terrain to the current model extents:
   • Specify the city model extents using the Model Properties dialog box.
   • Select Click Data Source Configuration > Raster tab > Clip to Model Extent.
4. For raster files, you can create or fill holes in the surface and specify elevation on Raster tab:
   • No Data Value: Creates holes in the surface, so you can import islands and other non-rectangular shaped regions. InfraWorks 360 converts the values you specify into “no data” values for elevations of the input raster. For example, turn values such as “-9999” (for ASCII grids) or “-32768” (for int16 GeoTIFFs) into regular “no data” values.
   • Fill No-Data Regions: Some terrain data sources have holes where the elevation is unknown, for example, an island surrounded by the sea (at zero sea level). To avoid displaying these regions as transparent, use this option to replace the “no-data" value with the value you specify.
   • Height Band: Specify the band in the raster that defines the height of the terrain.
5. For contour files, you can convert contours to grids on the Converter tab.

   Importing large contour files can affect performance or cause the import operation to fail. Such files cannot exceed 10 million surface points (approximately). Converting large contour files to a grid loses some precision, but improves performance.

   For Grid Size, enter a value between .5 meters and 500 meters. A smaller value will produce more detail, but will affect performance whenever you generate the model. Values under 2 meters are not recommended. The ideal setting depends on the amount of detail in the original contour file.

Advanced Tips

You can have only a single ground surface in each model, but you can use proposals to show different surfaces. For example, create one base ground. Then create a proposal and import a second surface within that proposal, containing the proposed ground. Switching between the proposal and the master version will change the appearance of the terrain.

You can create surface modifications by creating 3D coverage polygons. You can draw these by hand, to apply them as breaklines to the base ground, or import 3D polyline breaklines as Coverages. You can also create terrains from breaklines by classifying them as Terrain Contours on import.

You can divide contour files into smaller files that are tiled spatially (not by elevation or another method) and then select all the resulting files at once when you import them. There is no limitation on the size of raster grid terrains.