In Maya 2016, the mental ray for Maya user interface now enables complete rendering with minimal requirements to adjust settings. The defaults aim for immediate rendering of the most frequently used features.
Follow these steps to start a basic render of most scenes:
For more interactivity when using Render Current Frame, use the Progressive Mode control in the Configuration tab, under the Preferences section, Interactive Rendering sub-section. By selecting On from the drop-down list, you will see the render complete a frame of samples at a time, rather than completing a tile at a time. The default mode of IPR renders progressively only with IPR rendering.
In order to take best advantage of the settings, the following lights and materials are recommended when creating your scene:
Use mental ray materials such as the Layering (MILA) material, or MDL material.
Use mental ray lights such as the physical or environment lights. Select from among the options in Create > Lights > mental ray. section.
When using these suggested materials and lights, combined with adjusting Overall Quality, you can also use light and material sampling quality settings to refine rendering noise. For complex lighting variation, use the Lighting/Environment Lighting Quality controls. For complex geometric variation, use the Indirect Diffuse/Material Sampling Quality controls.
Lighting varies, for example, when using a high resolution, highly varying HDR image for your light texture. It can also vary when there is a large number of lights with varying intensity.