This algorithm strives to find planar surfaces (like walls and roofs) and ensures they remain planar during the reconstruction and simplification stages.

The planar simplification is based on a tolerance threshold:

If provided in pixels, the tolerance is defined in pixels in input photos: the simplification depends on input photos resolution.

If provided in meters (or units for non-georeferenced blocks), the tolerance is defined in the 3D coordinate space: the simplification is uniform over the 3D model.