mental ray attributes

mental ray Settings

Setup GeoShaders: Sets up a mental ray geometry shader used to generate the XGen render time geometry. By default, the setup is set to Automatically, which means it is done when a new Description is created (see XGen Hair phenomenon). To manually setup a shader for the current Description, select Manually and click Setup.
Render Mode

Live: XGen queries patches and guide animation directly from Maya. This mode does not support Motion Blur and reuses information the preview generated.
Batch Render: Reads geometry and animation from files. This mode is always on when using Batch Render. You must first export the patches and guide animation to caches. Use this mode to make sure your caches are properly exported using Batch Render.

See File > Export Patches for Batch Render.

Degree: Spline primitives can be rendered as linear segments or as cubic Bezier curves. Set to Cubic for Card primitives. This setting has no effect on Archive and Sphere primitives.

Linear: Renders Spline primitives as linear segments.
Cubic: Renders Spline primitives as smooth Bezier curves. You can use view dependent approximation.

Subdivisions: (for Linear Degree only) Defines the number of segments to use between control points.
Type: (for Cubic Degree only) Sets the type of mental ray approximation to use when subdividing render time hair Bezier curves or card NURBS patches.

No Approximation: Render time geometry is not subdivided.
Parametric Approximation: Subdivides render time geometry a number of times between control points.
Fine Approximation: Subdivides render time geometry until edges hit a given length in pixel size. This option is view dependent.

Sub Pixel Size: Subdivides geometry until edges hit a maximal length in pixel size. This option is view and resolution dependent. Values below 1.0 split the geometry within the same pixel. This is useful to render very thin hair with tube normals and a high number of samples. Values above 1.0 produce geometry that does not look smooth. It's useful to optimize render time if the geometry is far away from the camera.

Enable Motion Blur: Toggles motion blur effect on and off.

NoteIf you render single frames with Enable Motion Blur on, turn off the Update Preview Automatically ( see XGen Window toolbar) option the to improve Maya's Render View performance.
Motion Steps: Specifies how many motion path segments should be created for all motion transforms in the scene. The number must be in the range of 1 to 15. The default is 5.
Motion Blur By: Multiplier used to amplify the motion blur effect. Increasing this value reduces the realistic results, but can also produce an enhanced effect depending on what you want to achieve.

The higher the value, the longer the time interval used in the motion blur computation.
Motion Factor: Controls the fine displacement quality according to the amount of visual motion.
Keyframe Location: Specifies the motion offset when calculating motion blur.