Building Maintenance process

The Building Maintenance process can be used to update your 3D buildings when new lidar is available. It compares an existing 3D multipatch building layer with a new lidar dataset to check if there are any updates required due to new construction or demolition. If changes have been detected, these can then be merged back into the original 3D building layer.

To update your existing buildings, you will need:

Multipatch buildings.
Lidar with ground and buildings classified.

The Building Maintenance process accomplishes the following:

Detects changes changes between input 3D multipatch buildings and new lidar. The output are building update polygons where changes have been detected depending on the input parameters.
Creates LOD2 update buildings using the building update polygons and the lidar.
Merges the LOD2 update buildings with the existing 3D buildings.

Detect Building Changes

This step compares an existing 3D multipatch building layer with a new lidar dataset. The output is building polygon feature class where changes have been detected depending on the input parameters.

3D scene showing existig 3D buildings and new lidar — An example of existing buildings and new lidar. In green, changes are visible.

The Detect Footprint Changes tool requires a 3D building multipatch feature class and a LAS Dataset. The Vertical Change Threshold, and Minimum Area of Change parameters control the change detection. Vertical Change Threshold is the maximum allowable vertical difference between lidar and building multipatches before being flagged as a change in the buildings. Typically, new construction will not be less than one storey different in height. Minimum Area of Change is the minimum area required for a discrepancy in height between buildings and lidar to be flagged as a change area.

Detect Footprint Changes tool parameters — Detect Footprint Changes geoprocessing tool is available in the Update Schematic Buildings task. Use the tool to detect changes between existing 3D buildings and new lidar.

The Replace Changes parameter allows you keep the new footprints that were created incorporating the changes in geometry. If unchecked, the tool will preserve the original footprints of the changed buildings, allowing for manual updates to these extents.

The output is building polygon feature class where changes have been detected depending on the Vertical Change Threshold, and Minimum Area of Change.

Detect Footprint Changes result — Detect Footprint Changes tool output result symbolized by Update_Status.

Create Building Updates

Use the necessary steps in Publish Elevation Surface, Preprocess Buildings and Publish Schematic Buildings to create, review and modify the LOD2 building updates using the polygon feature class that was created in the Detect Building Changes step.

Create Buildings Updates result — Create Buildings Update result symbolized by Update_Status.

Merge Updates with Existing Buildings

Once you have created a multipatch LOD2 building feature class for the updates, you can use the Merge Updates with Existing Buildings step to merge the updates into the existing LOD2 building feature class. "Demolished" buildings and input features that intersect with the merge features are not saved in the output features.