Input data

Three types of input data can be used for reconstruction with City4CFD:

• 2D polygons,
• Point clouds,
• Existing building geometries, triangulated

2D polygons include building footprints and other surfaces such as green areas, water, and roads.

A point cloud is used to reconstruct terrain and calculate building heights. In case of a missing terrain point cloud, the terrain will be approximated as a flat surface.

For building reconstruction, you can use the combination of the following data:

• Building footprint polygons and buildings point cloud,
• Building footprint polygons with height/number of floor attribute,

You can import existing geometries in a number of formats listed below. The geometry must be triangulated and must have one distinctive bottom surface that can be attached to the terrain.

Supported formats for each of the data types are written in the table below.

Input data	Format
2D polygons	GDAL-supported formats
Point cloud	LAS/LAZ, TXT/XYZ, PLY
Imported geometries	CityJSON (triangulated), OBJ, STL, PLY, VTP, OFF

Information and tips on the preparation of polygons and point clouds can be found in their respective sections.