Bifrost 2.1.0.0 is a feature release with new features, performance improvements, and bug fixes.

Release Highlights

Bifrost 2.1.0.0 includes the following new features. Some of these features will result in broken connections when older graphs are loaded.

Please see Backward Compatibility Warnings for more information.

New geometry queries nodes (BIFROST-1256)

A new set of geometry queries nodes are available, with which you can get locations on geometry and then sample data from those locations.

The queries include:

• get_closest_locations
• get_closest_point
• get_points_in_radius
• get_raycast_locations

For example, geometry queries can be visualized using location_scope. The image below shows raycasting between simple geometries.

This feature breaks backward compatibility. Please see Backward Compatibility Warnings for more information.

Alembic improvements (BIFROST-4013, BIFROST-4117, BIFROST-1386, BIFROST-4090)

The following data can now be read from or written to Alembic files:

• Multiple meshes, with UVs and point properties
• Multiple strands, with per-point and per-strand user data
• Multiple points, with per-point properties

In addition, you can now write an animation to a single Alembic file instead of generating a separate file per frame.

This feature breaks backward compatibility. Please see Backward Compatibility Warnings for more information.

Reference counting (BIFROST-4016)

You may experience up to ten times speed improvement with graphs that make heavy use of indexing into arrays inside loops.

Improved FX graphs (BIFROST-4169, BIFROST-4226, BIFROST-4238, BIFROST-3853)

The basic_aero_graph and basic_particles_graph have been made both simpler and more powerful. They have been streamlined to include only the minimum nodes and properties required to run a basic simulation; at the same time, connecting additional available properties and custom properties to the graphs is now made easier with new menus and shortcuts. Furthermore, you can now visualize source and collider volumes. The source_mpm_sand, source_mpm_snow, and source_mpm_fluid nodes have new ports and shortcuts that enable you to easily add custom properties, and the default values of mpm_solver_settings have been adjusted to produce better results out of the box. You can also visualize the MPM collider levelset.

This feature breaks backward compatibility. Please see Backward Compatibility Warnings for more information.

Improved graph readability

The following features have been added to make your graph easier to read:

• A new icon to identify auto-looped ports (BIFROST-3920)
• The option to display the type of the node (BIFROST-4176)
• For nodes such as Value, get_geo_property and set_geo_property, the option to display their names or their values (BIFROST-1970)

Improved FCurve (BIFROST-1987)

The FCurve Editor now provides pre- and post-extrapolation functions, improved framing and clamping capabilities, and its UI, which includes a new thumbnail curve, has been improved to make it easier to edit your curves.

Wrangle the type of a port without adding a value node (BIFROST-1605)

You can now resolve the type of auto or overloaded ports on a referenced nodes by right-clicking and selecting from a list of suggested or supported types in the Value Types menu. This adds a value to the port, also known as an immediate value. These values are like invisible value nodes in the graph and can be used to resolve types. It is no longer necessary to create an explicit value node to resolve the port type on nodes such as set_geo_property.

File browser widgets now available on nodes with file path inputs (BIFROST-3920)

All file I/O nodes now have file browser widgets that are set to read and write the right type of file.

volume_to_mesh improvements (BIFROST-2673)

The volume_to_mesh compound has been improved with new functionality and a better workflow. You can now create a mesh from a fog_density directly without needing a level set. You can also select a custom property which can be used to create a mesh from a volume. The detail size mode now has an Automatic default option which will create the mesh with triangle sizes driven from the voxel size of the incoming volume, and fully supports adaptivity. Moreover, the Detail Size Scale allows for an overall adjustment of triangle size in any mode.

This feature breaks backward compatibility. Please see Backward Compatibility Warnings for more information.

convert_to_volume improvements (BIFROST-3357, BIFROST-4251)

Along with new port groupings that improve the UI, this node is now configured to convert an array of geometries into an array of volumes. If you use it to convert one geometry to one volume, the output is still an array. To obtain a single output and not an array output, connect the output of convert_to_volume to first_in_array. Furthermore, an automatic resolution mode has been added to the convert_to_volume node, which addresses issues related to voxelizing points in relative mode. This new automatic default mode detects the incoming geometry type, then voxelizes meshes in relative mode and points in absolute mode.

This feature breaks backward compatibility. Please see Backward Compatibility Warnings for more information.

Detect particle collisions (BIFROST-3714)

Particle collisions with surfaces and with other particles can now be detected and stored in two different properties, which can then be used to modulate influences, drive render data, and so forth. Look for the options on the particle_solver_settings.

Rendering large simulations is now possible (BIFROST-3855, ARNOLD-147)

You can now render large FX simulations that are over 4GB in size. In addition, it is now faster to transfer large data to Arnold for rendering.

This feature requires mtoa version 4.0.3.

New random_value node added (BIFROST-1273)

A random_value node has been added that computes one random value at a time instead of creating an array of values. Performance is improved as values are created as needed instead of being pre-computed ahead of time. This node also provides usability benefits, including the ability to create random values from point IDs (such as those produced by the particle systems).

Improved mpm_solver_settings default values (BIFROST-3717)

The mpm_solver_settings default values have been improved so that the point display shape is a sphere by default and does not face the camera.

Bending and breaking for make_mpm_shell, and improved UI for make_mpm_cloth (BIFROST-3432)

MPM shells now have the ability to permanently deform under enough stress. New controls can be found in the Breaking section of the node; however, note that breaking is not enabled yet, only bending. The Failure section for make_mpm_cloth has also been revamped under the name Tearing.

Improve the distance calculation in MPM simulations (BIFROST-3441)

The distance calculation used for collisions in MPM simulations is now improved with a new method that is more accurate at a lower cost. The detail size of the collider is also linked to the detail size of the solver by default, improving accuracy. They can be decoupled using an option on the mpm_solver_settings.

Improved handling of geometry

The handling of extra ranges by merge_geometry is now improved. Extra ranges are ignored so that meshes can be merged successfully even when an input mesh contains a range but not the corresponding data geo property. (BIFROST-4218)

Meshes remain valid even when there are remaining face_vertex_normal_indices after using erase_property to remove face_vertex_normals. (BIFROST-3856)

A valid geometry is always written to a .bob file even when you do not specify all the required properties. (BIFROST-3867)

New examples available in the Bifrost Browser (BIFROST-4691)

The following aero simulation graphs have been added to the Bifrost Browser:

• Fast Aero
• Missile Hit
• Vehicle Exhaust

Backward Compatibility Warnings

As mentioned above, the new features of this release bring with them a few changes that will break backward compatibility with previous versions of Bifrost (2.0.5.1 and below).

If you load a scene that contains a graph with a renamed or missing node, or a graph with a node that is missing an overload, warning messages will appear in the Script Editor that help you to troubleshoot the issue: for example, that message may indicate that a node definition cannot be resolved or that a parameter is invalid.

Geometry queries (BIFROST-1256)

The new geometry queries nodes include a change to the data type of the locations attribute: it is no longer an object, but an array of structs known as the GeoLocation data type. In addition, geometry queries nodes are now constructed differently: with a pair of operations – a build accelerator, and a sample accelerator. As a result, graphs that consist of geometry queries nodes from previous Bifrost versions may not be backward compatible in some cases. Explore the new nodes to reconstruct your graph.

Updated read_Alembic and write_Alembic nodes (BIFROST-4013, BIFROST-4117, BIFROST-1386, BIFROST-4090)

To support the new Alembic features, the read_Alembic node now has output ports for each of meshes, points, and strands; similarly, the write_Alembic node now has fan-in input ports for each of meshes, points, and strands. As a result, all alembic nodes from previous versions of Bifrost need to be replaced with those from this version.

The following FX graphs and nodes must be replaced by their new versions (BIFROST-4169, BIFROST-4238, BIFROST-4226):

• basic_aero_graph
• basic_combustion_graph
• source_air
• aero_solver_settings
• simulate_aero
• basic_particles_graph
• source_particles
• particle_solver_settings
• source_mpm_fluid
• source_mpm_sand
• source_mpm_snow
• mpm_solver_settings
• simulate_mpm

convert_to_volume (BIFROST-4251)

With the addition of the new automatic mode in the enumeration of the resolution type, this node may no longer be backward compatible with its previous version. If the node loads in error, replace it with its latest version.

volume_to_mesh (BIFROST-2673)

This node is now configured to accept an array of objects instead of a single one. You may need to recreate your connections to the node.

subdivide_mesh has been renamed to sqrt3_subdivide_mesh (BIFROST-4076)

sqrt3_subdivide_mesh uses a very specific subdivision algorithm relating to triangles, and the node has been renamed to reflect that fact.

Fractal noise and fractal turbulence now have float ports for frequencies (BIFROST-4321)

The behavior of fractal turbulence has changed: previously, zero frequency meant one frequency. It now behaves similarly to fractal noise, where zero frequencies mean no noise. This change allows you to smoothly animate up or down the number of frequencies, where 3.5 frequencies is the interpolated result halfway between 3 and 4.

Graphs provided in the Bifrost Browser are now in a new namespace (BIFROST-4312)

If you use any of the graphs burning_barrel, tearing_cloth, or waterfall_mist as compounds in your scene, you need to replace them with their new versions, as their namespaces have changed.

Strands and level set schema files have been renamed (BIFROST-4424)

The strand.json file has been renamed to strands.json, and the levelset.json file renamed to level_set.json. If your graph includes nodes that map to either ../resources/bif/schema/strand.json or ../resources/bif/schema/levelset.json, you will need to update the filename in these paths.

simplex_noise and curl_noise definitions have been moved to the bif folder (BIFROST-4450)

If your graph includes nodes that map to either of these noise nodes, you need to update their paths as follows:

simplex_noise: from ../resources/amino/jsonLibs/Noise.json to ../resources/bif/jsonLibs/noise_nodedefs.json

curl_noise: from ../resources/geometries/jsonLibs/point_nodedefs.json to ../resources/bif/jsonLibs/noise_nodedefs.json

Arnold Compatibility Information

• Arnold for Maya (MtoA) version 3.2.2 is the minimum supported version for the rendering of Bifrost content created from the procedural graph.
• The most recent version of MtoA is recommended for the latest bug fixes and performance improvements. In particular, note that some features of Bifrost 2.0.4.0 and higher are not supported by versions of MtoA prior to 4.0.0.
• MtoA version 4.0.0 or higher may only be used with Bifrost 2.0.3.0 or higher on Maya 2020, and Bifrost 2.0.4.0 or higher on Maya 2018 and Maya 2019.

To obtain the latest Arnold for Maya installer, visit the Autodesk Accounts portal.