You will need one of the following tools (most are free or have free versions):
Keep vehicles under 30,000 polygons for optimal performance convert obj to dff
To export to DFF, you need an add-on like or the RenderWare IO plugin. You will need one of the following tools
DFF materials point to texture names, not the image files themselves. Keep texture names under 32 characters, remove spaces, and avoid special characters. convert obj to dff
Go to File > Export . Choose RenderWare (*.dff) as the file type.
Paid license required for ZModeler 3; steep learning curve for the user interface. 4. Standalone CLI and Web Converters