Last day, I have found this project on the web and this is astonished!
It's a command line wich permitted to transform a file shape (for example) and minimum one file las (point clouds) in a file in format 3d (CityGML or OBJ or Shape 3D) !!
3dfier requires one or more 2D datasets and one or more elevation datasets as input. The 2D datasets can be of any OGR format, such as SHP or GML. The elevation datasets will be in LAS/LAZ.
The site is : https://github.com/tudelft3d/3dfier.
Do you think, one day, it would be possible to integrate such project in CloudCompare ?
It's just an idea ....