Choose this option to import a particular surface. All available surfaces will be displayed in the dropdown combo box. If there are no surfaces available, 'None' will be displayed.
Ignore Hidden Triangles (recommended)
If checked hidden triangles are excluded. For most normal situations, hidden triangles should be excluded.
Cogo Points
Choose this option to import only the coordinate geometry points contained in the file.
Auto group points (recommended for large files)
If checked, points will be grouped together into multi-point features in order to reduce memory useage.