This is my concept skid steer excavator that i designed and rendered it in fusion 360, you can find f3d (original version), and converted (fbx,obj,iges) files in attachement.
F3D (Autodesk Fusion 360, filesize: 49.7 MB), OBJ (OBJ, filesize: 40.8 MB), FBX (Autodesk FBX, filesize: 12.9 MB), IGE (IGES, filesize: 30.1 MB)