There’s the problem: you actually have six surfaces that need to be traced by the light rays for both reflections and refractions. Refractions set to the default of 6, and Max. If you havent changed the parameters, then you should see Max. To check this, go to the Renderer panel Rendering Algorithms rollout and look at the Maximum Trace Depth settings. It’s possible that you have the number of reflections and refractions set too low for the number of surfaces you have.

After rendering the scene, however, there’s something wrong: the inner surfaces of the glass don’t seem reflective enough, and the wine isn’t refracting properly. The wine geometry is just slightly smaller than the inner surfaces of the wineglass, and capped with a flat top. Say you’re rendering a (lathed) wineglass, with an inner and outer surface and a piece of geometry representing the wine. The mental ray renderer disregards the bias parameters in the Shadow Map Params rollout and the Ray Traced Shadow Params rollout.Instead, set it to a value close to zero (for example, 0.001 or 0.001). To get the same effect using the mental ray renderer, the light value must not be zero. With these settings, the light casts shadows but does not illuminate the scene. Using the default scanline renderer, you can set a light to have a value of zero, with a shadow color of white, and a shadow density of −1.To stop using the map, you must click the Map button and in the Material/Map Browser, assign NONE as the map type. When you assign a map to object shadows in the light's Shadow Parameters rollout, the mental ray renderer does not recognize the toggle for the map (to the left of the Map button), and renders the map whether the toggle is on or off.

(The Exclude button is on a light's General Parameters rollout.) To exclude objects from shadow casting, use ray-traced shadows.

Excluding an object from shadow casting doesn't work when you use mental ray to render shadow-mapped shadows.

To use Overshoot, use ray-traced shadows.

The Overshoot parameter for lights doesn't work when you use mental ray to render shadow-mapped shadows.

When you set up a scene for rendering with the mental ray renderer, keep the following tips in mind: Using Lights with the mental ray Renderer

Mental ray 3ds max 2017