PLAXIS 3D allows importing points, lines/polycurves,  surfaces and volumes, next to point cloud import. You can also import surface as the top and bottom soil surfaces of your borehole, in the Modify Soil Layers configuration window in the Surfaces tab. When importing a geometry file, a list of possible file extensions are shown.

Supported import formats

• STEP/STP: "Standard for the Exchange of Product model data" files
• BRep: Open CASCADE BRep file format
• DXF: supports only parametric geometry
• IFC: Industry Foundation Classes files
• Point cloud data in *.txt format [link]

With the internal changes for the geometric data model for PLAXIS 3D 2016, Plaxis will no longer support the import of triangulated geometry. This includes *.3ds, *.stl, *.dwg and triangulated *.dxf files. For supported types of older PLAXIS versions, see the attached document.