MTOR 3.0 Release Notes

(note: see also Slim release notes)

Table Of Contents
New Features
Bug Fixes

Policy Change

  • Glimpse deprecated - On Irix, Glimpse is no longer loaded by default. Also, Glimpse is not included in the release but can be downloaded separately. If you need to use Glimpse, first download the package and lay it atop a RAT tree. Next make sure that you set a new environment variable: RAT_LOADGLIMPSE.

New Features

  • New Menus - supporting all the new features of this release.
  • Initial support for Maya Subdivision Surfaces. Hierarchical edits are not supported.  Per-facet parameterization is also not supported.  Also, due to a limitation in the Maya 3.0's API, the new Auto Extrapolation feature is not available.  It is available with Maya 4.0.
  • Subdiv Auto Extrapolation.  You no longer need to create shading sets to apply different shaders to components of Pixar Subdivision surfaces. We've added a new attribute "Extrapolate Components" to control this behavior.  When set, MTOR will automatically derive facet groupings and attempt to maintain the appearance of a single continuous surface.  If you have a well-behaved and organized mesh, you can parameterize and texture mesh components independently.  This technique, if applicable, is far superior to a workflow requiring the manual specification of facet sets.  For more details please refer to the subdiv docs.
  • Manual and Automatic RIB Archiving MTOR now supports the generation of RIB Entity files which are appropriate for inclusion via RiReadArchive and RiDelayedReadArchive directives. You can manually archive a scene or selected objects by choosing the new RIB export option via Maya's standard Export or Export Selected entries. MTOR also supports new auto archiving functionality. Here you attach a Slim Archiver Appearance to a DAG node in your scene. MTOR will automatically archive all geometry below that DAG node. Slim's Archiver Appearance has several controls which govern the archiving and archive referencing process. AutoArchiving nodes are also the basis of the Level of Detail feature.
  • Multi Segment Motion Blur MTOR now has the capability to output multisegment motion blur directives to RenderMan. In certain cases, the standard, two sample, linear blur doesn't sufficiently capture the motion of an object. Now you can tag individual primitives or Auto Archive nodes with a Maya attribute (mtorMotionSamples) to cause the generation of more finely sampled motion. The support is limited to transform blur. Multi-segment deformation blurs are not supported. To add multiseg motion blur to a primitive, use the new Motion Samples submenu located in the  Attributes pullaside.  This creates an integer attribute named mtorMotionSamples. The default range should be 1 to 6 as PRMan has an arbitrary motion sample limit of 6. Note that when present, the mtorMotionSamples attribute can also be used to tag individual primitives for subframe motion even when your global setting implies frame motion.
  • CSG (Constructive Solid Geometry) - added new attributes to control the insertion of RenderMan CSG directives. You can now tag DAG nodes with standard RenderMan CSG directives - primitive, union, intersection and difference - to cause prman to perform CSG (booleans) in the renderer. MTOR already has support for Maya's booleans but there are some effects that you can only achieve in prman. For example, now you can motion blur the difference between two objects. Current support does not include visualization tools and requires that you understand boolean algebra and RenderMan's CSG specification.
  • Blobby Modeling - added experimental support for manual modeling of RenderMan Blobbies. Now you can individually position, orient and scale blobby primitives and assign primitive variables to them. Blobby primitives can be combined with blobby operators by tagging DAG nodes with special attributes. For more details refer to the prman appnote on blobbies.
  • Slim Adaptors - see Slim release notes for more details.
  • Context Render Global - can be used with Slim Adaptors.
  • Slim TCL Boxes.  These are like RIB Boxes but are used to associate TCL scripting state with Maya objects.
  • Maya's Level of Detail.  Note that Maya's level of detail doesn't support smooth transition regions.
  • PRMan's Level of Detail. The new attributes menu contains level of detail attributes. Basically you tag a number of different model representations as auto archiving. To each of these you assign mtorDetailRange attributes. Next you group these nodes below a Maya transform or lodGroup node and assign to it the MTOR LOD Control attributes. The end result is that prman can utilize the most efficient representation(s) for a given rendering and will smoothly interpolate between different reps.
  • Shutter Context Render Global - controls MTOR's RenderMan representation of the shutter and motion blur time coordination.  When set to stationary, MTOR always output's Shutter at time 0.  This makes archived RIB files more useful in that they can be included in RIB from any frame of an animation.  The old behavior is represented with a shutter context of moving.
  • Arbitrary Clipping Planes  - added support for the RenderMan 3.2 spec feature RiClippingPlane. You can use clipping planes to clip geometry in your scene along any number of arbitrarily oriented planes.  This feature will be supported in Pixar's upcoming version of PRMan - release 10.
  • Maya Particle Instancing MTOR now provides support for Maya's particle instancer. The basic workflow consists of setting up a Maya particle instancer and rendering. For more control, archivers can be attached to the source geometry. There are, however, certain limitations as MTOR does not support every type of per particle configuration. The rgbPP and opacityPP attributes are now carried to the RIB file in the form of RiColor and RiOpacity calls.
  • Support for different versions of Maya from a single RAT distribution.  We now support Maya3.0 and Maya4.0.  See the installation docs for more details.


  • New -sync option to the command "mtor control getvalue". When used with Glimpse disabled, Slim and MTOR aren't always kept in sync with respect to Render Globals.  This causes problems in mel scripts that query and set these values.
  • Inverse Crew - now you can use Maya sets to exclude the participation of specific objects in map calculations. Wherever you can enter the name of a "Selected Set" or crew you can now precede a set name with a '!' to indicate exclusion from map calculations.
  • Support for primitive variables of type varying.  MTOR determines the class of a primitive variable based on the array size of the Maya attribute.
  • MTOR's Attributes and Primitive Variables menu have been changed. Now you can select Maya objects with MTOR attributes attached. You can also detach the MTOR attributes via these menus.
  • MTOR now stores __Pref primitive variables for curve shape nodes and mtorCoordSysNodes. The latter is useful in conjunction with the new Blobby modeling features.
  • Added support for uniform primitive variables. This should be most useful for polygons and subdivs.
  • Added support for Maya's threshold parameter when rendering particle system blobs and tubes. Since prman and maya have different blob field functions you shouldn't expect that prman and maya blob renderings will match. The value of the threshold parameter lies in its ability to control the field function and, for example, animate the "melting" of a blobby.
  • Added support for new dirmapping functionality.
  • Optional "requires MTOR" behavior. When running without Glimpse, MTOR stores all its state in simple string attributes within a Maya file. This eliminates the "requires" that used to appear in all IRIX Maya files that had embedded MTOR information. Strictly speaking, MTOR is *not* required in order for Maya to read and write the file without data loss. Conversely MTOR *must* be loaded at the time a file is opened if you want to use MTOR functions on that session. (otherwise it will not be properly synchronized with the file contents).  You can address this problem in a variety of ways:
    • always autoload MTOR when starting Maya.
    • leave MTOR unloaded but load it before opening a file whose MTOR or Slim contents you wish to edit. After loading the MTOR plugin, re-open any open files to ensure that MTOR is properly synchronized.
    • set the ForceMTORRequires preference (in mtor.ini) to 1. This causes the "requires mtor" to appear in all Maya files saved while MTOR is loaded. Now when opening files with "requires mtor" Maya will automatically ensure the MTOR is loaded before reading the rest of your scene. You can still force MTOR to remain inactive (and not check out a license) by setting the MTOR_PLUGIN_NOLOAD environment variable.
  • Added new NURBS parameterization mode that results in matching RenderMan and Maya UV parameterization. By default, this new translation mode is disabled for backwards compatibility.
  • Added new RenderGlobal - zealousCaching, that controls caching behavior for selected object only rendering.
  • Sped up selected object only rendering.

Bug Fixes

  • added workaround of Maya Windows 3.0.1 bug in which files containing inverse kinematics (IK) didn't evaluate properly within standalone mtor.
  • importing Glimpse appearances that reside below the project location now works.
  • incorrect light link behavior involving sets and group nodes fixed.
  • added fix to deal with a Maya bug related which caused crashes related to the attachment of ensembles and surface shaders by allowing both surface shaders and ensembles to be attached to the same object. Note the ensemble overrides all other shaders  
  • output RiQuantize when not using Glimpse.
  • subdiv visualizations don't disappear when the camera is moved.
  •  fixed problems related to heterogeneous use of RATworkspace files. Fixed crash bug that occurred when loading a Windows workspace file under unix.
  •  texture conversion now occurs for non-attached specially named appearances (eg: World).
  • canceling during a remote RIB generation now works.
  • rendering with selected set operates independently of the objects in set attribute of camera controllers (1364).
  • MTOR now correctly filters out particles with 0 size or 0 opacity when rendering particles systems with the Sphere, Sprite or Square rendering mode.
  • map generator appearances attached to mtorCoordSys nodes now work correctly.
  • when scripting RenderMan Globals from within MTOR/Maya Slim didn't update the GUI for a few specific globals.
  • sometimes MTOR would ignore Slim requests for texture conversion resulting in texture missing messages.
  • fixed problems with multipoint and multistreak particle rendering.
  • the doExpand proc found in $RATTREE/etc/TORExpression.tcl is now called for each connected appearance to determine whether an appearance should be included in a particular rendering pass.
  • now you can attach multiple map generators to an object.
  • eliminated NaNs that would result in hair/fuzz queries. 
  • eliminated wrap behavior when jitter placement is enabled in hair/fuzz queries.
  • depth map generation was incompatible with job chunksize set to other than subframe. Bogus Alfred scripts were generated.
  • when exporting selection, empty Slim palettes no longer are exported.
  • reflection maps are correct when Pixel Aspect Ratio != 1.0.
  • you can now attach dsos via the mtor control attach scripting command.
  • sometimes MTOR would ignore Slim requests for texture conversion resulting in texture missing messages.
  • ensembles attached to shading sets or Maya shading groups now work.
  • removed overzealous reporting of name conflicts in the RIB declaration table.
  • curves now output the correct basis string in RIB.
  • fixed problem with motion blur on particle systems with a stationary shutter.

Pixar Animation Studios
(510) 752-3000 (voice)   (510) 752-3151 (fax)
Copyright © 1996- Pixar. All rights reserved.
RenderMan® is a registered trademark of Pixar.