Incorrect generation of the navgraph, for example, nodes are generated on the ceiling.
Troubleshooting Procedure
In the View menu, check the Point cloudNormals.
Under Point Cloud appearance, select color style = normals
If you don't see multiple colors, but only gray sparse points it means that normals were not properly generated and therefore the navgraph cannot be generated.
A Point Cloud is as a collection of data points in space that typically represent the external surface of an object or environment. Point clouds are used in various applications, including 3D scanning and mapping, and can be visualized and manipulated using Navvis IVION. You can perform actions such as panning, orbiting, cleaning up noise, cropping, and downloading data in formats like .e57 or .ply. The resolution of point clouds processed with NavVis Software achieves a minimum detail of 5mm, indicating the precision of the spatial data points.
Normals are perpendicular to the tangent plane line at a particular point on the surface. They yield especially useful information about a curved surface's characteristics but conversely can tell us much about the planarity of a flat or angular surface also. Normals can tell us the rate of change of curvature when a surface has an angular departure and tell us just how perfectly flat something is.