Images before and after scale. Also, I am not able to select the scaled geometries
Hi -
Those are typical symptoms of the “far-from-origin” issue. Your meshes are likely single-precision meshes and likely scaled with an origin that is far from the world origin. Please post a 3dm file and possibly the source of this model as well.
-wim
Thank you, Wim. I uploaded the model. The resource of the geometries is an AutoCAD 3d file from Digimap, which is unlikely to upload cause it’s too large. Model.rar (6.4 MB)
Hi -
I can’t tell if this model is before or after you scaled the geometry.
I tried scaling with both the world origin and a point on the geometry as the origin for scaling and a scale factor of 0.001. In both cases, the resulting objects looked fine here on Rhino 6.
You are running Rhinoceros 6.11 - Undefined, build 2018-10-17 ( 
) - the latest Rhino 6 version is currently 6.30. You might want to update your installation.
-wim
Thank you so much Wim! I have just updated it and it works absolutely fine!