In some cases, the error messages may be hard to understand. Below is the list of most probable reasons for such "confusing" messages:


Empty extent -  Bounding box is misplaced during Build Tiled Model or Build Orthomosaic operation and doesn't contain any information or all the cameras for the related area are disabled. 


Empty camera list - no cameras are pointing to the area of the orthomosaic generation.


Empty frame path - the selected operation (for example, import DEM) requires the project to be saved in PSX format.


Empty surface - Bounding box is misplaced during Build Mesh operation and doesn't contain any information.


Null dense point cloud -  missing dense cloud for the operation based on it (like mesh generation or classification). 


Null model - missing mesh model for the operation based on it (like mesh decimation).


Null point cloud -  missing sparse cloud for the operation based on it (like mesh generation).


Zero resolution -  Bounding box is misplaced prior to the Build Dense Cloud operation and doesn't contain any information (almost no tie points are present in the bounding box and therefore no depth maps can be generated).