creo4 config.pro option documentation for: INTF2D_IN_ACAD_IGNORE_3D 
intf2d_in_acad_ignore_3d
yes
, no
*
Allows you to skip the 3D solid entities in the 3D DXF or DWG files imported in the Drawing mode.
yes
- Ignores the 3D solid entities in the 3D DXF or DWG files imported in the Drawing mode and processes the 2D draft entities.
no
- Processes the 3D solid entities along with the 2D entities in the 3D DXF or DWG files imported in the Drawing mode and creates assemblies with the 3D data.
This configuration option is available as the Import 3DSOLID entities
option on the Import DXF
and Import DWG
dialog boxes.