DXF Files

DXF files are used to import and export objects to and from AutoCAD (and other programs that support this file format).

Keep the following in mind when you are creating your DXF geometry, and when you are deciding whether to convert by layer, color, or entity:

With AutoCAD Release 12, if you are using the AutoCAD Advanced Modeling Extension (AME), use the SOLMESH command on your AME models prior to saving the .dxf file.
With AutoCAD Release 13, you can use the 3DSOUT command to convert an AutoCAD drawing to mesh objects. This command creates a 3D Studio R4 (DOS) file that you can import into 3ds max.
After importing a DXF file, you might want to divide the resulting 3ds max into smaller objects.

Entities that are frozen or turned off are ignored.

The successful unification of face normals depends on the welding of coincident vertices. Sometimes, depending upon the precision of the model as it was created in AutoCAD, the vertices may not be close enough to be considered "coincident." They will not be welded, and the faces will not be properly unified. In this case, increase the Weld Threshold value in the Import DXF File dialog.

Converting by layer can result in objects consisting of many elements. In certain cases, some of these elements may have all of their face normals flipped the wrong way. You can detect this in the software by turning off Backface Cull in the Display panel, or by rendering the objects. Use the Normal modifier to correct this.

If you do not want to flip normals, you can either use 2-sided materials, or turn on the Force 2-Sided option in the Render Scene dialog.

If you are loading a large scene containing thousands of entities (such as 3D faces) and have chosen to load an object by entity, the conversion can take a long time. It also produces a huge number of objects to handle in the software. To avoid this, organize your DXF file so that these kinds of entities are grouped by layer, then make the conversion by layer rather than by entity.