I am working on a 3D project so I have to georeference 3D buildings which are created by 3D designer.
Does anyone know the solution?
I suppose the 3D designers have created 3D models using a CAD program. So, these 3D models are referenced into the local system of the CAD software. In order to georeference this 3D model, you need to find the transformation to apply to these coordinates to convert them toward your target CRS.
This transformation can be approximated by a translation + a rotation + a scale. This transformation parameters can be found by matching ground control points (GCP) coordinates in the CRS to their coordinates in the current model. At least 2 pairs of matching points are required to get all the transformation parameters.
Once you have the transformation parameters, you need to apply it to all the coordinates. A possible way could be to export your data into a text file format (like cityGML) and write a script to apply the transformation using your favorite programming language.
Looks like from your google-maps tag that you either need
or to use Sketchup