Stephen P. answered 05/10/19
Lead 3D Generalist with 20+ of Industry Experience
Sorry if you've gone through this already, but do you have lights in your scene, or is there something blocking the virtual lens of the camera from which you are rendering? Sometimes Mental Ray can generate black frames if the plug-in isn't loaded successfully. You may want to head to your plug-ins and reload Mental Ray (mayatomr) to see if that helps.