A basic Arnold translator for the apiMeshShape in the Maya devkit.
Copy ArnoldTranslator.dll into mtoadeploy/2017/extensions folder. Reload mtoa in Maya and the apiMeshShape can be rendered in Arnold now.
You'll need to modify apiMeshShape and expose apiMeshGeom and link with it. E.g.
//Modify apiMeshGeom* meshGeom(); in the apiMeshShape.h
__declspec(dllexport) apiMeshGeom* __cdecl meshGeom();
For more details, please check