If the [INTERNAL] format is used, the header is followed by the main section defining the position and height of buildings.
Click here to see an example section
The format chosen in the first line of the file (Format ID) is used here. Buildings are set into the area by assigning their height to the corresponding grid points (“20” in the example).
Only integer values are allowed as height information.

ENVI-met will assign the building to the corresponding grid boxes. In the vertical direction, the following rule is used to decide if a grid box is occupied by a building or not: If a grid cell is covered 50% or more by a building, it becomes part of the building. In the other case, it remains free.

Example
A 14m high building covers 3 grid cells with Δz=5m (split surface grid not counted).
Contrary, a 12m building will only be represented by 2 grids in the vertical.

Captured grids can cause problems in the model simulation.
A “captured grid” is a free grid cell that is surrounded by occupied grid cells only.
Click here to see an example for captured grids