Animation

Time Tool Enhancements
Additional placement and arrangement options were given for viewport navigation regions and a control key modifier during hauling was added to step between keys
Channel Haul Enhancements
A 'reset' button was added to the right-hand side of the tool, and more descriptive tooltips were added.
OpenSubdiv
Implement OpenSubdiv library for improved performance with deforming geometry by using OpenSubdiv features such as threading and GPU support.
Command Regions
Implements Command Regions, which allows use polygon selections to as clickable controls for rigging. The regions become visible when the mouse is over the mesh and can be clicked on even when the polygons or mesh item are locked from selection
Cut / Copy / Paste Channels
Adds ‘channel.copy’, ‘channel.cut’, and ‘channel.paste’ command, accessible from the Edit menu, context menu and keyboard shortcuts (ctrl/cmd-c, ctrl/cmd-x, ctrl/cmd-v) for Cutting, Copying, and Pasting values from the properties form and Channel list
Channel Locking
Adds a context menu item in the channel list to Lock / Unlock channels, using the ‘channel.lock’ command.
Curve Constraint Effector Improvements
The Curve Constraint Effector has been extended with various workflow improvements, and some minor changes that should improve the quality of the deformation, and make it more useful.

Assemblies/Schematic

Exposed Individual Relationships
Adds the ability to expose select graph rows and a mechanism to rename them using RMB
Channel Probe
Takes an arbitrary item input and allows you to access any channels on that item. Provides an easier way to expose channels as inputs to assemblies.
Quaternion Channel Modifiers
Added Quaternion Set Value, Get Value, From Angle/Axis, To/From Matrix, To/From Euler, Math, Conjugate, Normalize, Slerp, and Multiply Vector by Quaternion modifiers
String Find and Replace Modifier
The String Find and Replace modifier allows all occurrences of a search string to be replaced with a target string. By default, the search string and input string are case sensitive, but an Ignore Case option allows the case sensitivity to be ignored.
Nodal Support for Render Outputs
Added nodal components (new color/value channel, LinkSampleChannels, etc.) and override render pass to read nodal values.
Easier Assembly Creation
Added context entry to allow assembly creation by right-clicking on a node.
String Channel Modifiers
Added the String Compose, String Switch and String Constant Modifiers
Schematic Node IDs
Added a command to return the ID of an item's schematic node
Per-item Callbacks for Schematic
Added new PERITEM flag and PerItemFlags() callback. Result of callback should be cached per item/node.
Vector Channel Modifiers
Added Vector Orthogonalize, Vector Reflection, and Vector Multiply by Scalar Modifiers
Matrix Channel Modifiers
Added Matrix Vector Multiply and Matrix Invert modifiers
Drop Support for Schematic
Added the ILxDrop interface for Group, Node and Channel targets and the Drop Source interface for Assemblies, Nodes, Items, Channels and Graphs
Assign Channel Handles from Schematic
Added channel handle creation to the context-menu when RMB clicking on a node in schematic

Dynamics

Constraint Modifier
Added a procedural constraint modifier with the ability to glue objects by proximity or contact, clump them by volume or area, and support multiple constraint types.
Procedural Shatter Item
Implemented procedural shattering, which works with meshes and any items that expose a surface interface.
Dynamic Stickiness
Added a Stickiness channel to active rigid bodies to apply a Newtonian force to them after collision to make them stick together.
Shatter Improvements
Added support for using background particle sources or geometry to drive shatter patterns
Save and Load Simulations
Added ability to save and load basic channels as well as trigroups using an internal format
Additional Item List Filters
Added Dynamics, Particles, Forces and Volumes filters to the Item list filter types
Angle Limits on Dynamic Curve Joints
Changes the dynamic curve joint type to a ball-socket and adds angle limits to control bending amounts, as well as relaxation for improved simulation results.
Remove Dynamics
Added shift-modifier to expose alternate "remove dynamics" buttons in the Dynamics tools
Preserve Simulation Cache
Added API for bagging up bake caches from simulation channels and restoring them, then integrates them into the simulation commands
Improve Collision Emitter
Added similar implementation as the Constraint Modifier, making connections automatically based on selections and haveing it "just work" when added to the scene.

General

Play Mode
Added 'Play' mode when starting Modo without a valid license. This let's you open scenes, select things, change the time, open preview, render, etc but you can't do any changes and\or save the scene. In play mode the preview render is automatically set to 'slave' mode.
Global Select-through option
Adds a global preference to enable select through state by default, in Preferences > Defaults > Tool Settings
Global Auto-activate option
Adds a global preference to enable auto activation state by default, in Preferences > Defaults > Tool Settings
Macro Recording Controls
Add macro controls to the right of the Command History command entry, including a gear with popup options. These controls are automatically hidden when the command entry text field is selected to maximize entry space.
Cross-platform Crash Reporting
Adds a cross-platform crash reporting which gathers crash data and send it directly to The Foundry for use by Modo Developers, Quality Assurance and Customer Support

GL

Advanced viewport
Added a new hardware-accelerated photorealistic viewport that lets you manipulate geometry and materials in a real-time setting that accurately displays lighting and shadows, BRDF materials, reflections, screen-space ambient occlusion, high-quality
transparency, anti-aliasing, super sampling and a number of 2D post-processing effects.
Draw UV Edge Seams in 3D View
Adds a viewport option to display UV seams on the Active and Inactive Meshes, independently, with the color defined in the Color Preferences.
Draw Boundary Edges in 3D View
Adds a viewport option to display boundary edges on the Active and Inactive Meshes, independently, with the color defined in the Color Preferences.
3D Viewport Presets
Adds the ability to save presets of the viewport settings, with granular control over the 4 main viewport settings groups: drawing, visibility, active and inactive meshes
Apply Current Morph Setting
The current selected morph map is applied to all active and inactive meshes in MODO 801. MODO 901 can disable applying the current selected morph to inactive meshes by turning Apply Current Morph off.
Hair and Fur
Hair Mesh Workflow
Added 'separate' option to loop slice tool to build the inside polygons where the cut happens. The same thing can be done on the edge.split command.
Makes changes to tools to process guides used in hair meshes during common modeling operations such as: subdivide, loop slice and edge bevel.
Adds polygon PTAG to set polygons as invisible to render & with an override color in GL.

I/O

SVG Mesh and Image items
Added SVG mesh and image items for easy import and export of SVG artwork
Tiled EXR Conversion
Added context menu export options to convert existing scene image clips to Tiled EXR using various export options, saving the image alongside the originals or in a new location. Users can also access the converter through the command system.
OpenEXR 2.x Support
Updates the Modo OpenEXR library to version 2.x
MDD Export
A set of commands have been added to MODO 901, allowing selected meshes to be exported as MDD point caches. For each selected mesh, a single MDD file will be created, containing all of the vertex positions over the specified time range. This can be useful for exporting animation to another software package, or for round-tripping back to MODO as part of a production pipeline.
The MDD files can be added back to a mesh with the same point count and point order using the MDD Influence deformer.

Modeling

Topological Symmetry
Uses edge selection sets to define center edges as an option to implement a robust form of symmetry for deformed meshes.
Improved Slice Tool
Adds Split, Split and Fill, and Gap options to the slice tool.
Radial Align Tool
This implements a tool version of the script with support for N-sided shapes, as well as circles, with options shape rotation, radius, angle, weight, center, smoothing iterations, and flatten.
Improve Selection
Adds a new selection command to select elements inside the selected loop.
Edge Slice Across Multiple Edges
Adds "Multi Slice" mode to cut multiple polygons at once.
Extend Loop Selection
Edge loop selection stops tracing connecting edges at point where has odd number branches. This allows users another behavior for loop selection to continue tracing connected edges even if number of branches are odd by choosing most aligned edge.
Fill Quads Pattern Fill
Adds the pattern fill mode to the Quad Fill command
Linear Align Tool
Implements the Linear Align tool with options to interpolate points linearly between the endpoints or to fit a curve to the selected points. Additional options to set uniform spans, apply the weight of the alignment, iteratively smooth the results,
flatten a polygon selection, or align edges to length.
UV UDIM Packing
Adds option to pack UV islands into multiple UDIM tiles.
UDIM Indicator for UV Workflow
Adds packing indicators on the UDIM space, displays the UDIM number and adds autospan options, updates the UV tools and commands to support UDIM regions, makes it easy to easily move and fit UVs into different UDIM spaces, and adds a show coverage option.
UV Copy/Paste Based on Topology
Allows copy and paste UV transfers between geometry with the same topologies.
UV Rectangle Tool
aligns multiple strip UV islands to regular grid patterns with one operation.
MeshFusion
MeshFusion is now a fully integrated feature of MODO 901
Add 2D Curve Polygon type
This polygon type is similar to Text polygon type, but it uses connecting boundary curve, bezier or polyline like Spline Patch polygon instead text glyph. This is useful for rendering simple vector graphics consisting of bezier curves. Curve fill polygon can contain multiple outer loops and the holes. The 2D plane of curve fill polygon is computed by 1st, 2nd and last vertex positions.
Convert UVs to Mesh
Adds a new option to the Texture menu to convert the currently selected UVs to a planar mesh.
UV Packing w/ Edge Straightening
Implements tool to straighten UV edges between two UV points
Curve Generator Bank Angle
Implements option to twist knots by interpolating the entire twist angle
UV Straightening Option for Relax tool
Adds Straighten option to the UV relax tool which straightens the boundary of the UV island and then relaxes the internal positions.
Categorize Mesh Properties
Creates separate tabs for Mesh properties, breaking Surface data and Curve data into separate sub-tabs
Freeze Deformations into Morphs
Update poly.freeze command to store displacement vertex positions into morph map instead of replacing source positions.
Calculate Mesh Volume
A "Calculate Mesh Volume" command is now available from the bottom of item list's context menu.
Calculate Mesh Center of Mass/Gravity
The "Calculate Center of Mass" command calculates the center of mass/center of gravity for a mesh & places a locator, parented to the mesh, at that location as a visual aid.
Axis Rotation Tool Improvement
You can now snap the advance handle to the indicators of rotation ring to quantize your rotation angle.
Selection Improvement
Select Between has been mapped to Shift-RMB, e.g. select a polygon and shift-RMB on another, the polygons in between will be selected.

Painting

Masking with Gradients
A 'mask' option has been to the parametric ink tool. It is on by default and what it does is that instead of interpolating the FG\BG colors it simply modulates the alpha channel. So for example if you use the 'incidence angle' parameter the ink will be opaque on the sides of the object and transparent where the surface is perpendicular to the viewer.
Painting Improvements
Fixes stroke blending between successive semi-transparent sub-strokes, fixes density interpolation between sub-strokes, optimizes stroke evaluation on long strokes, improves scanline performance and quality for subpixel sampling, improves brush orientation during drawing, reducing jittering and discontinuities, and fixes UV tile drawing anti-aliasing.

Particles

Particles Improvements
Updates auto-wire for surface emitters to auto-connect to the selected mesh, and for source emitters and volume items to auto-connect to any selected particle source item.
Particles Constraints
Particle constraints allow the position and rotation of individual particles to be read, as part of a rig. This allows items to be constrained to particles, and can also be used to allow a particle simulation to be affected by another particle source.

UI

Drag and Drop Workflow
Updates the mouse inputs to allow use of keyboard modifiers (i.e. shift key to add a preset) when dragging and dropping either before or after they start dragging
Drop Mapper
Adds a Prefs > Input > Drop Mappings form where users can sort drop actions relative to each other within different modifier key combos.
Drop Behaviors
Implements ILxDrop support for presets to Preview and 3D viewports, allow users to hover before dropping to get a dropmenu of options for applying the preset, as well as modifier keys that can be used instead.

Rendering

Physically-based Materials
Adds the new Physically Based shading mode (default) which simplifies material settings to use index of refraction (IOR) and adds GTR anisotropy and blurry reflections with GGX specular highlights, based on a Disney paper. When the Physically Based shading model is being used, two new options for the clearcoat effect are now available.
Roughness: This controls the sharpness of clearcoat reflections in the same way that specular roughness affects blurry reflections. 0% provides sharp reflections as in previous releases.
Bump Strength: This specifies how much the clearcoat is affected by bump and normal maps. 100% corresponds to the behavior in previous releases while 0% means the clearcoat is unaffected by bump and normal maps."
Preview Render Baking
Add ability to do texture baking with the preview render.
Wireframe Texture
Implements the wireframe texture
Tension Texture
Implements a tension texture with options for angle-based (torsion) and area-based (tension) measurements of relative mesh deformation. These measurements can be used to drive color and value via gradients.
Multiple Importance Sampling (MIS)
Implements diffuse and specular Multiple Importance Sampling (MIS) area, point, directional, spot, and IES lights and cylinder lights, as well as making all visible to the camera just like area lights. Each light also adds an importance multiplier so that users can increase the number of rays for a given light to directly address problem shading/noise.
Adaptive Light Sample Allocation
improves efficiency with light sampling and light linking. Each light also adds an importance multiplier so that users can increase the number of rays for a given light to directly address problem shading/noise.
Deferred Mesh Item
Implements a deferred mesh item, which is like a static mesh that's been offloaded into an external file. The item in the scene takes minimal memory (just a locator), but when rendering the relevant geometry gets streamed from the file. Geometry can be added and removed from the Deferred Mesh or split off into Deferred Surfaces
Deferred Mesh Enhancements
Implements a multiple bounding box GL representation, which can be used to display a reasonable representation of the full resolution mesh with minimal memory impact, as well as the requested controls on the item.
Physical Daylight Improvement
"The Hošek-Wilkie Physical Skylight Model has been updated to include computation of direct solar radiance; the direct sun light seen in the solar disc. The new model takes into account both 'limb darkening' and atmospheric 'inscattering'.
Improved Progressive Renderer
Changes the preview refinement algorithm to include convergence rate and displays the progress towards convergence along with the elapsed time of the render.
Projection Workflow
Adds the projection shader and texture culling
Improved Tone Mapping
Adds Reinhardt Luminance and RGB tone mapping algorithms
Render Hide Polygons
Polygons can be hidden for rendering just like they can be hidden for modeling. This is achieved with 2 new commands in the 'View' system menu: 'Render Hide Selected' and 'Render Unhide'.
Preview Slave Mode
"Preview can be set to 'slave' mode, what that means is that it will react to any changes to the current scene by saving the current render, reloading the scene and restarting. Note: this mode is automatically enabled when Modo starts in 'play' mode. This is useful if you want to use a second computer as a render computer that always computes a render of the scene you are working on.
Gradient Fill Image
A procedurally generated image with a color and alpha gradients defined by two points on the image. The points are independant of the image size and the shape of the gradient can also be chosen from multiple options.
Exposure Control Improvements
There are now two ways to control the brightness of the rendered image for a particular render output. The choice can be made using a popup menu in the render output item properties and also in the render window's Image Processing tab.
White Level: This is the original method in which a particular radiance or luminance is specified that corresponds to white (pixel value 1 1 1) in the image.
Photographic: This is a new method in which the brightness is determined by the exposure time, f-stop, and film speed, as in a real camera. The exposure time is a function of the camera's blur length and the scene's fps setting. To make setting the exposure time easier, a new Shutter Speed control (measured in inverse seconds) has been added to the camera properties form. The film speed is specified by a new ISO channel in the render output item.
Preview Render Autosave
Adds autosave to Preview Render as well as protection against accidentally resetting.
Faster Progressive Render Updates
Adds a generic tableau listener and visitor to the SDK, then uses them to improve performance and incremental updates
Progressive Render Fast Shading Mode
Adds a Shading Full / Shading Fast toggle to switch between standard, full updates and isolated, faster updates only on the changed surfaces

Sculpting

Background to Multiresolution
Implement a command to transfer multi-reso displacement vectors from background mesh
Multiresolution Sculpt Layers
Implements MR Sculpt Layers, allowing users to add multiple layers to a Multiresolution Catmull-Clark mesh. The Layers palette is accessible from the Sculpt HUD ‘Layers’ button. Layers can be imported/exported individually and their opacity changed using
the context menu in the Layers palette
MR Sculpt Layer Opacity Drive Modfiier
Adds a channel modifier to adjust the opacity of individual MR Sculpt Layers, which can be used and rigged in schematic. The modifier is added by right-clicking on the layer and selecting Add Modifier

SDK

Python TD API
Implements a Python API that sits on top of the Python SDK to allow easier interaction with Modo in a more intuitive and natural way.
Add Qt Support to Mac and Windows Modo
Ports the Modo UI to Qt, providing users the ability to create custom PySide views in all Modo platforms, not just Linux
SDK: Tree View API
Implements the tree view API, with interfaces for setting columns in the view, adding and updating attribute changes, shape changes and updates, input remapping for context menus, support for badges and tooltips, command support for edits, and events such
as mouseover, multiple selection, and drag and drop.
SDK Improvements
Adds several new capabilities to the SDK, including Quaternion types, a Value Service, Core Python Changes, Package Documentation, Solid Drill improvements, Polygon Slice improvements, Polygon and Curve interface improvements.

Surface Generators and Replicators

Replica Rigging
Adds ability to drive parameters of prototypes attached to replicators (for prototypes with compatible implementation, such as procedural items like the Sphere and Rock items, as well as rigid rigs. Adds feature packages to the replicator so that it is aware of all particle features. Adds quantized variants for time and random variations.
Procedural Rock Item
Adds a procedural Rock item which can be driven directly by its channels or rigged to easily add variation to a scene with replica rigging
Texture Replicators Using Vmaps
Adds vector vertex map support to replicators by adding the vertex feature when the vector vertex map is selected on the texture locator.
Texture Switch Node
Add a new channel modifier that has texture items as inputs and has the channels as outputs: value and color.

Volumetrics

Voxel Item
Implements the VDBVoxel interface in Modo, allowing loading, displaying and rendering of OpenVDB datasets, allowing interface with particle simulations, volume items, mesh items and to generate meshes from voxel data.