Render settings: mental ray tabs in Maya 2016

Quality tab

Show Advanced Quality Settings

When enabled, advanced settings are shown in the Quality tab. It is stored as a user option, so stays consistent from scene to scene.

Basic Quality Settings

The following describes the settings when the basic defaults are used and Advanced Quality settings are not enabled.

Sampling

Overall Quality

Controls the samples per pixel globally across the scene in unified sampling mode, the default mode. The number of samples per pixel varies depending on the quality measured locally per pixel region. This is the primary control for quality vs. speed. When there is noise in the scene, typically increase this quality.

Lighting Quality

Controls the number of light samples at an intersection point, when a ray hits an object, and the material is processed. When actively enabled, the default for new scenes, mental ray uses light importance sampling (LIS) to sample the lights. This disregards the explicit samples settings in each area light in favor of more sweeping scene control. Lighting quality takes into account the number of lights, both point and area, as well as trace depth and other factors to ultimately determine how many light samples to use.

Environment Lighting Quality

Controls the number of environment light samples to use. Currently, separate from lighting quality and enabled when environment lighting is enabled. This control is currently duplicated in the IBL node Attribute Editor User Interface.

Indirect Diffuse (GI) Mode

This selects the technique for providing indirect diffuse reflection and transmission. All use the same quality control to control the sampling quality of diffuse materials.

Off

No indirect diffuse sampling occurs

On (GI Prototype)

Uses the latest GI technique in mental ray to provide indirect diffuse sampling. This uses the quality control for determining indirect samples (GI rays). The Diffuse Trace Depth control affects how deep in the eye sample path this technique will be used.

Finalgather

Uses the Finalgather technique for indirect diffuse sampling using the interpolated FG map. The quality control affects samples and pre-sample density, and should provide sufficient control for most usage.

Finalgather Force

Uses the Finalgather technique for indirect diffuse sampling without the interpolated FG map, i.e. brute force, as each eye ray which intersects a diffuse surface shoots a number of FG rays. The quality control affects samples, the number of FG rays that are used.

Indirect Diffuse Quality

Controls the number of samples split out for a diffuse interaction at a material. For the basic default Global Illumination (GI) mode, this controls the number of GI rays. In Finalgather (FG) mode, controls the number of FG rays, as well as the FG point density and other FG controls.

Note:

If inheriting a scene with Finalgather (FG) on, the FG controls it affects will not be changed until this quality slider is touched. So the scene will remain able to be rendered as saved. However, once touched, this control will affect many FG controls that can only be seen in the legacy FG settings section. For legacy FG settings to be visible at the bottom of the Quality tab in the Legacy Options section, Advanced Settings must be enabled.

Material (MILA) Quality

Controls the number of samples split out for layering library (MILA) materials with either glossy reflection/refraction or scatter components.

Sample Lock

Locks the jittered locations of the samples within pixels from frame to frame. When turned on, this option ensures that the samples occur at the same location within each pixel, which is important to help eliminate noise and flickering results in a slowly moving camera sequence. For faster action, the noise from frame to frame may actually be a benefit.

Volume Sampling
Volume Samples

Controls the number of samples in Maya volumes, but not currently for Bifrost rendering. See Legacy Render Settings for more detail.

Filtering

For each pixel, samples are blended together using the filter type and filter window size as specified. The window is centered on the pixel and the size units are in pixels. A 3x3 window means the pixel blends samples from all the surrounding pixels.

Note: With unified sampling as the default sampling mode, to increase detail, generally use a Gauss filter with a smaller filter window size such as Gauss 2 2.
Filter
Box (default)

Samples are averaged together within the filter size window. It is called Box because that is the shape seen when graphing the equal sample weights against their distance from the center of the pixel.

The types other than box weigh samples higher at center of the pixel. As samples move further away from the center of the pixel, their contribution weight falls off as defined by the filter shape. This causes samples and details at the center of the pixel to be more "present" in the final computed pixel in the framebuffer.

Triangle

This filter shape defines a linear fall-off for sample contribution. Triangle offers better results than Box, but is rarely used as there is not much time penalty to use Gauss relative to other render settings.

Gauss

Gauss uses a bell-shaped curved fall-off for sample contribution. Samples near the center of the pixel have virtually the same contribution weight, but rapidly, though smoothly, falloff as distance from the center of the pixel increases. With unified sampling generally providing higher samples per pixel in detail areas, Gauss no longer requires a minimum filter size of 3, therefore lessening the tendency to make images more blurry.

Mitchell, Lanczos

Mitchell and Lanczos are alternatives to Gauss that tend to sharpen the final computed pixels. Mitchell sharpens less than Lanczos, but both may create detail where it may not exist, so use with care. Typically, this filter type is used for rendering single images for high quality print, not for animation sequences where the manufactured detail might pop. It is recommended to not judge the quality of an animation on a single rendered frame within its frame range.

Because Lanczos and Mitchell filters may produce negative values, these filter types are “clipped”variants to ensure positive values. The filtered result samples are clipped to the min/max range of input samples. The final pixel in the image will therefore not contain any out-of-range values produced by the filter.

Filter Size

Controls the filter size in pixel units used to interpolate each pixel in the rendered image. The larger the value, the more information from neighboring pixels. A value of 2 2 means the filter window is 2x2 pixels surrounding the center of each pixel. Large values tend to blur the image, though different filter types also affect how much is blurred. Since box is an average, and not weighted toward the center of the pixel, most blurring is apparent with that filter type using a large filter window size.

Trace Depth

When an eye sample originates from the eye, each interaction along a given path increases the ray traced depth count. The interaction type can identify different types of counts. For example, Diffuse reflection or transmission counts toward the Diffuse, while glossy or specular reflection counts toward Reflection, and glossy or specular transmission counts toward Refraction.

Diffuse

When an indirect diffuse mode is used, this affects the trace depth at which indirect diffuse sampling continues to be used. Note that a value of 0 currently means that the first indirect diffuse samples are taken, but then no others, when an indirect diffuse mode is enabled. The count starts after the first diffuse interaction, not at the eye. Compared to the rest of the depths below, this means this number is one less in relative depth to the other interactions for a given eye sample.

Post-diffuse glossy/specular interactions

After the first diffuse surface is sampled, this allows sampling of surfaces including glossy/specular reflection and refraction. Without this, the sample path will only continue for diffuse-to-diffuse interactions. Currently, this only controls the final gather indirect diffuse modes.

Reflection

The maximum number of times a ray can be reflected off reflective surfaces.

See also Max Trace Depth.

Transmission

The maximum number of times a ray can be refracted through non-opaque surfaces. Note that transparency is treated separately in Maya-specific materials, where the transparency is unlimited.

See also Max Trace Depth.

Max Trace Depth

While the Reflections setting and Transmissions setting each set the maximum number of times a ray can reflect or transmit/refract, this setting sets total number of interactions along a given sample path that can occur. For example, if reflections = 5, refractions = 5, but max depth trace = 4, then any combination of reflection and transmission interactions can take place, up to a maximum of 4.

Geometry

Displace Motion Factor

Controls the displacement tessellation quality according to the amount of visual motion. Reduces tessellation density as objects move faster.

For fast moving objects, images with comparable visual quality may require fewer displacement tessellation details as compared to static or slow moving objects. So this attribute provides an automatic way of adjusting the displacement quality according to the amount of motion for a given object part. Geometry is reduced only in the areas of the object with strong motion.

This attribute modifies the amount of geometry reduction as compared to the static case. A value of 0 disables the feature. 1 is the default and higher values provide more reduction.

Advanced Quality Settings

Sampling

Legacy Sampling Settings: When not using Unified Sampling, the legacy sampling controls appear in the Sampling section. These controls are the same as those documented in Render Settings: Legacy mental ray tabs, under Quality Sampling.

Advanced Overall Sampling
Auto Samples

When on, the default, the Overall Quality will control minimum and maximum samples. The Min Sample setting roughly follows the quality, and the Max Samples is roughly 200*quality.

Error Cutoff

Rarely used, when quality is extremely high well above 2, it can be an optimization to turn up the error cutoff, so that sampling is no longer performed in areas with low measured quality.

Quality as Color

Control quality and error by component (Red, Green, Blue, Alpha).

Advanced Light Sampling

Light IS

Light Importance Sampling (IS) mode On or Off. When on, the default, all light sampling is controlled by the lighting quality control. Higher quality raises sample counts. All the light samples use importance across all lights, area as well as point lights. When On, the following light controls are also available.

Light Samples

The number of samples used for each area light. The local per-area light samples are ignored when using Light Importance Sampling. This value is used instead. However due to the mechanism, the actual samples used per area light may vary as importance is determined for each intersection being lit. The default is 3 samples per area light.

Light IS Resolution

Controls the resolution of the hemisphere above intersection points that determines light importance, where the most important light comes from. A value of 1.0 is the default. Rarely used, you might raise this value if complex, highly varying lighting occurs. Imagine the resolution of sky map above each intersection point, and how much resolution that map would need to be to detect light differences. Very similar to analyzing an image-based environment light, but localized to each intersection point.

Light Sample Reuse

Lights are sampled for importance according to the above resolution for each intersection point. When processing the lighting for the materials, re-use these samples rather than take new ones. Potentially useful when using high resolution HDR textures for lights, in which this could produce smoother results faster, though at the risk of some loss of detail. The default is off.

Material (MILA) Quality

When advanced settings are on, further quality controls are provided. The material quality settings are relative, such that controlling Material Quality will continue to control both glossy and scatter quality. With defaults of 1.0, this means that material quality is multiplied by glossy or scatter quality to determine for each respective component how many samples to split out.

(MILA) Glossy Quality

Controls the number of samples split out for layering library (MILA) materials with glossy reflection/transmission components. As noted above, the glossy samples are also affected by material quality.

(MILA) Scatter Quality

Controls the number of samples split out for layering library (MILA) materials with scatter components. As noted above, the scatter samples are also affected by material quality.

Legacy Options

Sampling Mode
Unified Sampling

The default, encourages the simpler mechanisms of basic mode, in which raytracing is always on, and scanline is turned off. The following two modes also change what appears for basic Sampling control.

Legacy Rasterizer
See Render Settings: Legacy mental ray tabs.
Legacy Sampling
See Render Settings: Legacy mental ray tabs.
Maya Shader settings

Shadows, Reflection/Refraction Blur limit control what is implemented in Maya material shaders

Acceleration

For the legacy BSP control, see this section in the Render Settings: Legacy mental ray tabs and the Legacy tab named Indirect Lighting. See that Indirect Lighting tab in Legacy Render Settings for more information on the indirect modes of Global Illumination and Caustics with photons, Importons, Final Gathering, Irradiance Particles and Ambient Occlusion shader control.

Scene tab

Show Advanced Settings

When enabled, advanced settings are shown in the Scene tab. It is stored as a user option, and therefore stays consistent from scene to scene.

Basic Scene Settings

The following describes the settings display6ed when the basic defaults are used and Show Advanced Settings is disenabled.

Cameras

The Cameras section of the Scene tab controls settings that are shared by renderable cameras. The mental ray translation will ensure that the settings in this section apply to any camera being rendered.

Primary Framebuffer

The primary framebuffer attributes specify the main color render image created by mental ray. When using multiple passes this is often referred to as the main Beauty Pass. Internally, mental ray uses 32-bit floating point values for most sample calculations. When creating the final pixel values, the following attributes specify what is stored as a result of rendering, converting as necessary.

Data Type

Select the number and type of channels, as well as value type, for the main color render image.

Each image file format supports one or more data types. In addition, each file format is associated with a default data type. If you select a data type that is not supported by the file format that you have chosen, then mental ray for Maya will use the default data type associated with the file format instead. Most common with multiple passes is the OpenEXR format and that supports the commonly used data type RGB/A (Half) and (Float) for colors.

Use Deep Image Format

When using OpenEXR file format, deep data can be stored. This means that multiple values can be stored in each pixel, each reflecting a different depth. This currently applies to all the color layers stored in the image file. Please refer to OpenEXR specification for more details on the format.

Passes

Because of filtering, sample information is lost when saving a render to a pixel-based image format, as is the current common workflow. For this reason, when using passes, prefer to use additive light passes whenever possible. The passes have been set up as nodes in Maya ahead of time, and only need to be enabled to be rendered. Typically the passes are written into the main exr output file containing the main render pass seen in the Render View.

Contrast All Buffers

Occasionally, you may notice aliasing on the edges of your render passes that does not exist in your overall beauty pass. The sampling algorithm analyzes a local error measurement in the rendered image to determine whether or not a given image region requires finer sampling. When off, only the primary framebuffer samples are used for this measurement. Therefore, it may yield aliasing in render passes that contain high contrast detail in areas where the main beauty pass is smooth. Enable this option to analyze the error measurement in all color frame buffers being rendered.

The render may be faster when the option is turned off, at the risk of compromising image quality for a given pass when the multi-render pass workflow is used.

MILA Light Path passes

These passes can be rendered simultaneously for multi-pass rendering workflow. They are a simplified version of mutli-pass workflow for mental ray. Separating light interaction into diffuse, glossy, specular and reflection or transmission points, these passes distinguish between direct and indirect light with respect to the

Currently, these passes work only with Layering (MILA) library materials. Select mila_material when assigning a material to an object.

  • Reflection
    • Direct Diffuse

    • Indirect Diffuse

    • Direct Glossy/Specular

    • Indirect Glossy/Specular

    • Direct Glossy

    • Indirect Glossy

    • Direct Specular

    • Indirect Specular

  • Transmission
    • Refraction

    • Glossy Refraction

    • Specular Refraction

  • Scatter
    • Front Scatter

    • Back Scatter

  • Emission
    • Emission

Split Glossy/Specular Passes

By default, glossy and specular reflection is combined, and the same for glossy and specular transmission. This means that perfect mirror reflection is combined with blurry reflections. If you’d like to separate these in passes, use this option.

Split Direct Light Passes

Direct lighting for diffuse, glossy, specular materials can be split by light sets containing lights. Currently a maximum of 4 light sets are available to split direct light contribution. Any other light is then combined into the environment light contribution, such as direct_diffuse_env_light.

Edit Light Sets

For convenience, creates the four light sets, and brings up the Set editor window to move lights into light sets for the Split Direct Light Passes option.

MILA Matte Pass
Use Matte Passes

Automatically create and use a matte pass for each MILA material. If the material is a member of the following matte pass material sets, it will be grouped into that matte instead. Currently, this will place a white matte in the extra color buffer of each mila_material. This matte color can be changed there.

Create Matte Pass Material Set

Creates another matte pass material set to group matte passes together. And brings up set editor.

Edit Matte Pass Material Set

For convenience, brings up the Set editor.

Standard Utility passes
Depth
Distance between the camera and the intersection point.
Normal
Interpolated surface normal. If bump mapping is applied to the shading network, it will appear in this pass.
Motion Vector

3D motion vector. In mental ray for Maya, the 3D motion vector is expressed in internal space, typically the world space.

UV

A UV pass converts UV values to R/G values and creates a rasterized version of UV space. Using a UV pass, you can replace textures in 3d renderings as a post-process, without having to track new textures in place.

Position
A position pass writes position (x,y,z) values to R, G, B values. Use this pass for relighting workflows in compositing. Currently, this uses world space, but will have an option for object space.
Label

The tag/label/id of each object is placed in the pixel. This pass renders to a separate file by default.

Ambient Occlusion

Ambient Occlusion pass is processed in parallel with other rendering and uses GPU if available.

AO Max Distance

At the special value of 0, the default, this has no max distance setting, No occlusion only if an AO ray hits no objects. If inside a room, set this distance to an amount that allows an AO ray to consider it a no hit at a max distance less than the room size.

AO Falloff

When AO Max Distance is not 0, determine the fall off type for when the distance is reached. This is useful in scenes with objects that

Environment
Image Based Lighting

When you click the Create button, a new IBL node is created, replacing any currently connected node. (Though multiple IBL environments can exist in a scene, only one can be used at a time.)

For descriptions of the attributes in the IBL node, see Image based lighting node attributes.

Physical Sun and Sky

When you click the Create button, a network containing the mia_physicalsky, mia physicalsun, and directionalLight is created. Maya automatically connects all the necessary attributes from the three nodes for you. This network is connected to all existing renderable cameras.

For more information, see Simulating the sun and sky and Adding sun and sky to your scene.

Note:

Image based lighting and physical sun and sky are not designed to work together at the same time. It is therefore recommended that you either use one or the other.

Emit Environment Light

When enabled, creates a light from the environment whether it is procedural like the Environment Sky Light, or an image-based like Environment Image. The Environment Sky uses the mia_physicalsky, and Environment Image uses a small set of the IBL attributes.

Note: This control duplicates the same control that is visible in the AE for the IBL named Emit Light.
Shutter

When using motion blur, the shutter open interval is primarily determined by the Shutter Angle in the Camera. For example, a shutter angle of 144 degrees equates to a shutter open 40% of the total frame time.

Note:

The open and close shutter time is translated to mental ray as the beginning and ending of a frame, in order to more flexibly enable the features below.

Motion Blur

Select one of the following options:

Off

Turns motion blur off.

No Deformation

No Deformation only considers the position of objects at the Shutter beginning and end point (open and close points). Ie, it considers only the transform node changes for animation.

Full

Full is slower to render, but gives true (that is, exact) motion blur results. In addition to object transform motion, each deformed surface is also being translated "per vertex". Select this method for motion blur of objects being deformed by animation, such as jiggling arms and jello-like motions, where the vertices are moving and jiggling as the animation occurs.

Motion Blur By

This is a multiplier used to amplify the motion blur effect. Increasing this value reduces the realistic results achieved, but may produce an enhanced effect if that’s what you want to achieve.

The higher the value, the longer the time interval used in the motion blur’s computation.

Keyframe Location
Specifies where the keyframe time is located within the open shutter interval, effectively placing the keyframe position inside the blurred motion. Select one of the following options:
Start of Frame

The key frame is at the start of the frame, at the beginning of the motion blur. If an animated object is traveling to the right, then the key frame will be at the left edge of the blurred motion.

Middle of Frame

The key frame is in the middle of the frame, in the middle of the motion blur. If an animated object is traveling to the right, then the key frame will be in the middle of the blurred motion. This option is the default.

End of Frame

The key frame is at the end of the frame, at the end of the motion blur. If an animated object is traveling to the right, then the key frame will be at the right edge of the blurred motion.

Note:

Keyframe location flexibility allows you to match preferences of editors, or scenes with difficult matchmoves. Although a 3D animation system typically considers the key to be in the center of the motion blur, an editor might want to line it up at frame time 0, the start of the frame. Synchronizing with the easiest match move could find you using the end of frame, though used less often. Also note that if the speed of animation is not even, the center of the motion in time, may not match the center of motion in blur distance.

Motion Steps

If motion blurring is enabled, mental ray can create motion paths from motion transforms, which will match the number ofmotion vectors on vertices that also create motion paths.

This option specifies how many motion path segments should be created for all motion transforms in the scene. as well as motion vectors per animated v The number must be in the range 1 to 15. The default is 1.

Shape

Controls the shape of the shutter open interval if openness is graphed over time. Speed of making it to a fully open shutter.

Box

Shutter opens and closes instantaneously. With a shutter angle of 144 degrees 40% of the time the shutter is open.

Trapezoid

Shutter opens and closes linearly at 80% shutter efficiency. Designed to work best with a 50% or 180 degree Shutter angle such that the overal shutter open time becomes 80% of 50% = 40% to match typical filmed footage. Therefore, the default shutter angle must be changed by the user, as changing this setting does not affect the Camera Shutter Angle Setting.

Lights
Light Decay

If Quadratic is selected, will set all lights in the scene accordingly

Light Intensity Units

Used by lights that understand this shared render setting: Physical Area Light, Object Light .

Light Set Names LPE Handles
Rather than use a numbered light set system, use a light set name for identifying light contribution sets. Not implemented yet.
Shadows
If you prefer to use ray traced shadows, the settings in this section offers all the shadow settings available in the legacy mental ray Render Settings.
Materials
Architectural (MIA)

Convert Architectural to Layering

Makes best effort to convert mia_materials to mila_materials

Layering (MILA)
MILA Clamp Output

Clamps the output of mila_material. This is an enable, and the next control is the value.

MILA Clamp Level

The level used for clamping, typically between 1 and 10, based on desired output.

MILA Use Max Distance Inside
Use the max distance for reflection internally for colored glass. This is the default.
MILA Scatter Scale

Scale all mila_scatter effects globally. This is very convenient for re-using materials across different size scenes. It multiplies by the local scale control, if exposed, in the component.

Textures
Auto MipMap
Currently not enabled.
Objects
Auto User Data Attributes
Currently not enabled.
Add User Data

Opens a user data window to apply the same type of user data to all selected objects.

Name

User data named this is attached to all selected objects

Type
Select among color, vector, scalar and so forth.
Apply to Material

In the materials assigned to the selected objects, find the component identified and refer to this named user data.

Value

The basic value of the user data of the type selected. See variance.

Default

If using Apply to Material, and the material is also assigned to an object that does not have this user data, use this default value.

Variance

If greater than 0, applies this variance to the user data of the type selected. The variance is selected randomly per object user data attached. Use this for example to get a variance in color in a large set of objects with the same material.

Advanced Scene Settings

Cameras

Primary Framebuffer

The remaining settings shown in advanced mode are the same as those in the legacy mental ray Render Settings, Quality Tab, Framebuffer section.

Configuration tab

Show Advanced Settings

When enabled, advanced settings are shown in the Configuration tab. It is stored as a user option, so stays consistent from scene to scene.

Basic Configuration Settings

The following describes the settings when the basic defaults are used and Advanced Configuration settings are not enabled.

Preferences

Interactive Rendering
Progressive Mode

Progressive rendering begins with a lower sampling rate and then progressively refines the number of samples towards the final result. Progressive Mode

IPR Only

Use progressive sampling in the Render View with IPR mode only.

On

Use progressive sampling in the Render View with both IPR mode and normal current frame render.

You can also enable this feature by enabling IPR > IPR Quality > IPR Progressive Mode from the Render View window. If IPR Only is on, then the Render View menu item will show it enabled; however, if you turn the menu option off, then back on, it will switch Progressive mode to On.

Translation

Contains options for specifying the settings and items to be included when rendering a Maya scene with mental ray for Maya. Slightly renamed from legacy settings for better understanding that these are attributes of the translation process before rendering or mi file export.

Use Exact Hierarchy

Tries to preserve the DAG hierarchy during processing. This produces additional mental ray instgroup entities. There are certain unresolved material inheritance issues in this mode, but it works well in the general case. Deeply nested DAG hierarchies may be translated much faster compared to the standard Maya iterator mode that always flattens the DAG. Default is off.

Use Full Pathnames

Uses the full DAG path names instead of the shortest possible name for mental ray scene entities. This is not required to generate a valid scene, but ensures reproducible names even if DAG entity names are reused in Maya. On the other hand, with deeply nested DAG hierarchy names, you may exceed the maximum supported name length in mental ray. Default is off.

Translate Textures First

Collects all file texture references in the scene first. This ensures that missing texture files are reported early in the process, but may slow down scene processing depending on the number of file textures being used. It may also write out texture references that are never used in the shading graph, because it doesn't perform a complete scene graph traversal for performance reasons. Default is off.

Render Particles

Allows you to render particles. Default is on.

Render Particle Instances

Allows you to render particle instances. Default is on.

Render Fluids

Allows you to render fluids. Default is on.

Render Hair
Select one of the following options:
Hair Geometry Shader

The geometry shader creates the hair. This option should be used for rendering interactively in Maya and offers the best Maya Hair translation performance.

Off
Select this option if you do not want to export hair.
Hair Primitive

Select this option to convert Maya hair to native mental ray hair so that it can be rendered with mental ray standalone. This option can be used for rendering interactively in Maya or for exporting the file to render with standalone but better suited for mi file rendering.

Render Maya Glow (Export Post Effects)

Creates the Maya Glow frame buffer pass, in order to render post effects. When used, this is processed as an output shader on pixels.

Use Vertex Colors

Translates all the CPV (color per vertex) data for all the meshes in your scene. This can be process-intensive, so do not turn on this attribute unless necessary.

Advanced Configuration Settings

Preferences

GI
GI Prototype Mode
GI Next

Modern GI algorithm with few extra controls. Relies on Indirect Diffuse Quality primarily and the Diffuse control in Trace Depth

GI GPU

The initial GI GPU prototype GI algorithm, runs in both CPU and GPU

Use GPU

Enable to use GPU when GI GPU mode is selected

Performance

Expand the Translation section to adjust the Performance options when Show Advanced Settings is enabled. See the Options Tab, Translation section, Performance sub-section in Render Settings: Legacy mental ray tabs for descriptions of these attributes.

Customization

Expand the Translation section to adjust the Customization options when Show Advanced Settings is enabled. See the Options Tab, Translation section, Customization sub-section in Render Settings: Legacy mental ray tabs for descriptions of these attributes.

Contours

Contours only work with legacy sampling techniques.

If Unified Sampling (the default and currently preferred working mode for most scenes) is on when you choose to render contours, a warning occurs reminding you to switch to use Legacy Sampling.

See the Contour section in Render Settings: Legacy mental ray tabs for descriptions of these attributes.

Diagnostics tab

Diagnostics

Diagnose samples

Shows how spatial (eye) samples were placed in the rendered image, by producing a grayscale image signifying sample density. Creates special informational passes for diagnostics including density, error, and time per sample.

Feature Overrides

See the Features tab, Extra Features section in Render Settings: Legacy mental ray tabs for descriptions of these attributes.

Scene Overrides

See the Options tab, mental ray Overrides section in Render Settings: Legacy mental ray tabs for descriptions of these attributes.

Legacy mental ray Passes tab

Select Windows > Settings/Preferences > Preferences to open the Preferences window. In the Rendering section, enable Show Maya Legacy Passes to display the Passes tab in the Render Settings window.

See the Passes tab section in Render Settings: Legacy mental ray tabs for descriptions of the legacy mental ray render passes.