DXF is a messy format and pretty hard to handle. If you design your Graphics e.g. in Blender, then you might end up with something like this: DXF export in Blender is messy, so better export it to STL ...

This freeware (open source) app converts vrml files to a 3d DXF File. Simple use the wrltodxf.exe and give at first parameter the 3d File ( wrl / x3d / stl or obj Wavefront) you want to convert to a ...