Coltop3D is a software for geological analysis and analysis of 3D point clouds. It is designed for interactive analysis of geological structures at local and regional scale from photogrammetric, airborne and terrestrial LiDAR data and Digital Terrain Models. This software supports multiple applications and is particularly optimized for visualization and structural analysis in the following areas: structural geology; natural hazards; mines and quarries; civil engineering. Coltop3D can import any point cloud from LiDAR and photogrammetric data, as well as Digital Terrain Models. The software calculates the orientation of the geological structures for each point of the imported cloud. Coltop3D is a powerful support for calculating and highlighting different families of geological structures, thanks to its unique visualization and selection tools. The orientation of the selected points can be visualized in a stereonet and basic statistics are calculated for each family. Coltop3D can represent 3D data according to many criteria (RGB, altitude, shading, etc.), and more particularly according to its remarkable color wheel hue-saturation-brightness according to the topography. Thus, each azimuth-dip orientation is represented in a unique color code, allowing rapid detection of geological structures.