Prepare data for import

When using imported polygons as initial shapes for building generation, consider the following when creating the source data in a third-party application:

  • Polygons that are drawn counterclockwise result in shapes facing upward. This is the desired orientation.
  • The first edge of a polygon is interpreted as the front of the generated building. This is useful when you want to create different facades for the front, side, and back of a building.

    Polygon's edge orientation
    A polygon's edge orientation is shown.
  • Depending on the file format, CityEngine interprets group, entity, or object names as names for start rules. Consequently, you must group the meshes and assign names that are valid CGA shape grammar identifiers (no special characters, space, and so on).
  • Some tools have different units for exporting. Review the exported file in a text editor to see the actual dimensions. Most import wizards allow you to apply a uniform scaling of the imported data.