The error message is the following: display-object: No rendering surfaces have been set. This occurs when the imported STL-surface has no intersection with the mesh. A typical issue is that the STL-surface has been read with the wrong setting for the units, i.e. [m] instead of [mm]. Please check 1) dimensions of mesh 2) dimensions of STL-surface This is easily done by first displaying the STL-surface in the import dialog, and then adding the boundary meshes with the option “Add to Graphics”, in order to show both at the same time. In case you see only either one, it is most probable that the wrong unit has been selected during import.