An ASCII DXF file in two forms may be created containing triangulated surfaces of the same type as displayed in 3D Layer visualisations. Two types of definitions of three dimensional triangle objects are supported, as different CAD systems, such as MicroStation and Vulcan, will only read in one or other of the object types. The two types are 3D Faces, and Polylines. Each surface selected in the 3D Options window is saved as a triangulated surface, with continuous surfaces saved within single "DXF Layers". If, for example a stratigraphic horizon is broken by a fault plane, two distinct DXF layers will be created.

The naming convention for stratigraphic layer names is as follows:

S02040005

where the initial S indicates that this is a stratigraphic surface, the next two characters (02 in this example) refer to the stratigraphy number, showing that this is the second stratigraphy defined in the deformation history, the next two characters (04) refer to the surface number within this stratigraphy, and the last four characters (0005) are an internally generated code which uniquely identify which contiguous volume this layer sits in the model. Faults, unconformities, plugs & dykes all cut a geological model into discontinuous volumes, and each distinct volume, across which other surfaces are discontinuous, are labelled internally by the software.

The naming convention for discontinuity layer names is as follows:

B003006009

where the initial B indicates that this is a discontinuity surface (Fault, unconformity, plug or dyke), the next three characters (003 in this example) indicate event number of the discontinuity causing deformation event, the next three characters (0036) indicate the internally generated contiguous volume code of the volume on one side of the discontinuity, and the final three characters (009) indicate the internally generated contiguous volume code of the other side of the discontinuity.

The reason for adopting such a complex scheme is that it allows related surfaces to be grouped in one of two ways: stratigraphic or discontinuity surfaces can all be selected by their age, or individual contiguous volumes may be selected by their volume code, so that all the surfaces surrounding a particular contiguous volume may be identified easily so that a triangulated 3D volume can be created.