OPengine Web Tools
FBX to OPM
Note that this will upload your .fbx to the server to convert and then it will delete the .fbx. The .opm and other files will remain for at least a day. Please compile the FBXtoOPM Tool in the OPengine and run it locally if that's a problem.
FBX File to convert
If left empty Take 001 will be used if Animations are checked