Laser scanned buildings usually have a vast amount of 3D-faces.
I would guess that this is the problem. Do you have the possibility to check the number of faces?
was it FreeCAD ?
I thought I read somewhere that this is possible..
at least this is a good theme for new AI software tools..
like a pdf/dwg reader that converts architektur plans into BIM.
whenever Relux will accept BIM all this capturing work could be saved..