The AutoCAD DXF geometry export converter writes out the scene database
as either 3-point or 4-point polygons using the 3DFACE or POLYFACE MESH
entities. Polygons with 5 or more vertices, concave polygons, or polygons
with holes are automatically triangulated. All polygons will be assigned
DXF color # 1.
If the file is written using the POLYFACE MESH option then there is no
need to weld the geometry data when the DXF file is read into another
program (since the data output to the DXF file will be automatically
welded by this converter).
Dialog Box Options
The following information explains the various options on the dialog box:
Separate Polygons Into Separate Layers
This option determines which layers each polygon will be assigned to:
By Object Name
All polygons belonging to a single object will exported to its own DXF layer with the layer’s name being derived from the object’s handle name. This is the default.
By Surface Name (Material Name)
All polygons that share the same surface name (material name) will be exported on the same DXF layer. The layer name will be derived from the surface name.
One Layer
All polygons will be exported to a single DXF layer named “LAYER1”.
Output Polygons As...
This option determines whether polygons will be exported using the DXF Polyface mesh entity or the 3D FACE entity:
Polyface Mesh (smaller files)
Polygons will be exported using the DXF Polyface Mesh (PFACE) entity. This creates a more compact DXF file and can be read in much faster than a file written using the 3D FACE entity. All polygons are stored in two arrays consisting of a vertex array list and a face list.
In AutoCAD you can use the PEDIT command to stretch, rotate, scale and move the mesh but not to edit it. To edit the faces, use the EXPLODE command to break the mesh into separate 3D Face entities.
NOTE: Files written using this entity type already have their vertices automatically welded by this program’s export utility.
3D FACEs (larger files, more common)
Polygons will be exported using the DXF 3D FACE entity. This creates much larger files since each polygon is stored to the file one-by-one. However, most DXF reader programs can read this format so it might be necessary to use this option if a DXF reader cannot understand the Polyface Mesh format.
Force all Polygons to be Triangles
If this checkbox is check-marked then all polygons will be saved to the DXF file as triangles. By default it is not check-marked so the polygons are saved to the file as either 4-sided quadrilaterals or 3-sided triangles.
Reverse Orientation of Polygon Faces
If this checkbox is check-marked then the orientation of the polygon faces will be revered. This might be necessary if the destination program which reads in the DXF file requires a different polygon orientation than used by this program.
Dialog Box Options