Model/3D Formats Opened by ARCHICAD

Use File > Open or File > Interoperability > Merge to open a Rhino 3D Model file (.3dm) directly in ARCHICAD.
Use the File > Open command to open a .skp file directly in ARCHICAD.
Important: Make sure that the merged Google Earth model to be opened
Collect 3D geometry placemarks into a single Library Part: If you check this, ARCHICAD will generate a single GDL object for multi-geometry placemarks (instead of separate ones). This can reduce the time it takes to import the .kmz file.
Display 3D geometry placemarks without fills: This option can speed up navigation in large models.
Use the File > Open command or File > Interoperability > Merge to open or merge an .stl file directly in ARCHICAD. An opened or merged STL model will be opened as a Morph in ARCHICAD.
More about STL format: http://en.wikipedia.org/wiki/STL_(file_format)
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Go to File > Open > Open file
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Go to File > Interoperability >Merge