1 New In Coreform Cubit
1.1 Release Notes: Coreform Cubit 2022.4
1.1.1 U-splines
Coreform Cubit now supports U-spline construction on volumes meshed with the following mesh schemes:
Map
SubMap
Sweep
Sphere
Polyhedron
TetPrimitive
1.1.2 Graphical User Interface
1.1.2.1 Selection by entity name in graphics window
The right click menu now provides an option to select entities that share the same name. It will select entities that have the same prefix up to the "@" character.
1.1.2.2 Select Chamfer Chain
When selecting a chamfer surface, the ‘select chamfer chain’ option is available in the right-click context menu.
1.1.3 Meshing
1.1.3.1 New Mass Increase Ratio metric added to Cubit
The Mass Increase Ratio metric is based on the timestep metric and can be used as a guide to determine how much an element’s mass can be scaled during analysis, to typically increase timestep. Users specify a minimum ‘target timestep’ and then use this metric to see how much an element’s mass will be scaled by to meet the specified timestep. Available for use on tets and hexes.
1.1.3.2 Geometry-Aware Spider Blocks
When creating spider blocks with the command:
Block <id> Joint [Vertex <id> | Node <id>] Spider {Surface|Curve|Vertex|Face|Tri|Node} <range> [preview][Element Type{ bar | bar2 | bar3 | BEAM | beam2 | beam3 | truss | truss2 | truss3 }]
and geometry (surface|curve|vertex) is referenced, the spider block is linked to that geometry, allowing the spider to update/regenerate the BAR elements if the mesh on the geometry is delete, remeshed, or translated.
1.1.4 Geometry
1.1.4.1 ACIS kernel updated to Version 2021.1.0.1
The ACIS geometry kernel has been updated to Version 2021.1.0.1.
use idless journal files, or
use the Python API to create idless Python scripts.
1.1.5 Sculpt
1.1.5.1 New Sculpt options
stitch_parallel option combines parallel files when no Nemesis data is included
match_sidesets_nodeset to more precisely define boundary between sides when using ‘match_sidesets’ option.
material_name, sideset_name, and nodeset_name added to define names on materials, sidesets, and nodesets respectively.
sideset and nodeset to allow for user-defined sidesets and nodesets based on xyz bounding box boundaries.
large_exodus to generate output Exodus file(s) to allow IDs greater than 2^31 (2.14 Billion).
input_mesh option under the gen_sidesets option. Used with the input_mesh option where an exodus file is used as the base grid. Only sidesets and nodesets defined in the input exodus mesh are transferred to the output mesh.
1.1.6 Graphics, Utilities, etc.
1.1.6.1 Enhancements to Free Entity Selection
The ability to select free surfaces (sheet bodies) has been added to the command:
Select Free [surface <id_list>] [curve <id_list>] [vertex <id_list>] [add|remove]
1.1.6.2 Added support for Corvid Velodyne files
Cubit now supports exporting files for use in Corvid Velodyne, via the command:
export velodyne ’<filename>’ [overwrite]
1.1.6.3 New CubitInterface functions
CubitInterface is Cubit’s python module that provides extensive capability for querying and modifying data in Cubit. The following functions were added to CubitInterface for version 2022.4.
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1.1.7 Defects Fixed in Coreform Cubit 2022.4
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1.1.8 Enhancements in Coreform Cubit 2022.4
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1.2 Release Notes: Coreform Cubit 2020.2
1.2.1 Graphical User Interface
1.2.1.1 New Geometry Power Tool Diagnostics and Solutions
The Geometry power tool includes interactive diagnostics and solutions for defeaturing and repairing CAD models. New diagnostic tests have been added along with rapid solutions for repair. Updated and expanded diagnostics categories include Traits and Assembly Checks.
Traits: This category includes tests for common surface configurations in a geometric volume. This release introduces new and improved Traits diagnostic tests:
New Holes and Chamfer Chains diagnostics tests allow for rapid identification of these common characteristics so users can quickly remove or verify them. These tests identify sorted lists of collections of surfaces that can be expanded and visualized. Collections of Holes and Chamfer Chains are sorted by radius and thickness respectively. New associated context solutions also provide for fast removal of selected collections of surfaces.
The Blend Chains diagnostic test replaces the Blends diagnostic. Blend Chains now identifies sorted collections of blends that are associated with the same blend chain. This allows rapid identification and removal with a single command.
Assembly Checks: The new Assembly Checks category of diagnostic replaces Overlap Checks. It consolidates all diagnostics for checking interactions between volumes in an assembly into one category and adds additional valuable tools for resolving issues prior to imprinting, merging and meshing.
The new Volume Gaps test will display pairs of volumes that are not touching but are closer than the Volume Gap threshold.
Volume Overlaps is now updated to generate contextual simplified solutions for removing overlaps between pairs of volumes.
The new Volume Misalignments diagnostic test will identify volumes that are touching but have entities that would otherwise create slivers when imprinting. This also includes new capabilities for quickly visualizing and resolving misalignments between volumes.
Volume Contacts replaces the Overlapping Surfaces diagnostic. It identifies volume pairs that are touching, but have not been merged along with their overlapping surfaces.
The new Mergeable Geometry diagnostic replaces the individual vertex, curve and surface mergeable categories. This diagnostic includes entities that are coincident and can be merged.
A new option for specifying Tolerant Imprint and estimating an Imprint Tolerance is now provided. Changing the Imprint Tolerance can change the results of the Gap, Overlap and Misalignment diagnostic results.
1.2.1.1.1 New Command Panel Navigation Method
A new, optional, method for navigating the command panels has been added. This new option can be toggled on and off under Tools > Options > Command Panels. The obvious benefit of using this “breadcrumb” navigation method is gaining additional vertical space for command panels which will eliminate the need for scrolling in many cases.
1.2.1.1.2 Support for Dark Mode
Support for Dark Mode has been added to Cubit 2020.2.
1.2.1.1.3 Display Volume Overlaps and Neighbors from Context Menu
Two new options are available in the graphics window when volumes are selected:
draw nearby volumes All volumes close to the selected volume(s) will also be drawn. This is useful when working with large assemblies to view only local parts for defeaturing or boundary condition assignment.
draw volume overlaps Draws the wireframe representation of the selected volume(s) and any volumes it overlaps. The overlapping region shared by the volumes will be displayed in red
1.2.1.1.4 Tetmesh and Trimesh GUI Command Panels
A new command panel for setting options for the tetmesh scheme is now available supporting all new local and global options for tetrahedral meshing. This panel now includes two separate tabs for setting options for surface meshing and volume mesh options. The trimesh panel has also been updated in a similar manner for setting options for the trimesh scheme.
1.2.1.1.5 Reduce Bolts Command Panel
The new reduce command (described below) uses a new command panel to rapidly set up parameters to simplify and assign boundary conditions to bolt connectors. Access the Reduce options in the command panels by clicking on Mode/Geometry > Entity/Volume > Action/Modify and using the dropdown to select Reduce.
1.2.1.2 Meshing
1.2.1.2.1 New Meshing Collapse Commands
The following commands are good for collapsing low quality tets and triangles. The user specifies a mesh entity to collapse and optionally a metric. The operation attempts to collapse the mesh entity, ensuring that the quality of surviving neighbor mesh entities does not degrade lower than the mesh entity getting collapsed. The specified metric is used to determine quality. If not specified, "Scaled Jacobian" is used.
If the collapse can not be done without degrading quality, no collapse is performed. To collapse triangles, use the first two commands.
Only triangle and tets can be collapsed, not faces and hexes.
collapse edge <id> [scaled jacobian|aspect ratio|shape|shape and size] collapse tri <id> [scaled jacobian|aspect ratio|shape|shape and size] collapse tet <id> [altitude|aspect ratio|aspect ratio gam|distortion|inradius|jacobian|normalized inradius|node distance|scaled jacobian|shape|shape and size|timestep]
1.2.1.2.2 Enhancements to Meshedit Command
The [keep node<id>] option indicates which node to collapse the edge to. The [compress_ids] option was also added to preserve the previous behavior of compressing the mesh id space after the collapse.
meshedit collapse edge <id> [keep node <id>] [compress_ids]
1.2.1.2.3 Mesh Intersection Group Naming
A new option was added to the find mesh intersection command to allow naming the group created containing the intersecting mesh. If no group name is specified, the group is named mesh_intersect for 3D elements and surf_intersect for 2D elements.
find mesh intersection {block|body|surface|volume} <id_list>> [with {block|body|surface|volume} <id_list>] [low <value=0.0001>] [high <value=0.0001>] [exhaustive] [worst <num_worst>] [draw] [log] [group <’name’>]
1.2.1.2.4 Normalized Inradius Metric for tet10 Elements
A new quality metric normalized inradius is now included as a standard option for all quality commands that affect tets and tris. It is intended to measure quality of TETRA10 and TRI6 elements, but can also measure linear (TETRA4, TRI3) elements. While most tet metrics, such as the default Shape, only take into account the 4 corner nodes of the tet, the normalized inradius uses the ten nodes of the tet. This is especially useful when measuring quality for a coarse tet mesh at curved surfaces where mid-edge-nodes can be projected to geometry distorting the elements. An example of using the new metric in a command to display the mesh quality is as follows:
quality volume all normalized inradius draw mesh
1.2.1.2.5 New Node Constraint Options
When tet meshing with TETRA10 elements or setting a block element type to TETRA10, the mid-edge nodes on the surfaces can be projected to follow the geometry. In some cases, those projections can form an invalid or poor quality element when the linear version of the elements would otherwise be acceptable. Previously, Cubit provided the set node constraint command to control mid-edge node projections. The smart option allows for projections only if element quality does not degrade below a quality threshold. This version provides a new tet quality parameter and threshold parameter.
set node constraint [on|off|smart][tet quality [distortion|normalized inradius]] [threshold <value=0.15>]
With the introduction of the normalized inradius metric in this release, the tet quality setting can use this new metric as criteria for projecting mid-edge nodes. The new threshold value permits setting of a value at which mid-edge nodes will be straightened if the quality falls below. The node constraint options can also be set in the Options or Preferences dialog under Mesh Defaults and can be saved between Cubit runs.
1.2.1.2.6 Parallel Tetrahedral Meshing
With this release, users have access to MeshGem’s parallel tet mesher, TetraHPC. Parallel tet meshing is an option in the Tet Mesh Command panel mentioned above. Parallel tet meshing is threaded and will support up to 8 concurrent threads.
1.2.1.3 Geometry
1.2.1.3.1 Reduce Command
The reduce command prepares a bolt for analysis by quickly breaking down its geometry into its simplest form and applying boundary conditions. The different options allow the bolt to be simplified, decomposed into its component parts, overlap removed and fitted to surrounding geometry, imprinted and merged with surrounding geometry, meshed with a qtri scheme on the plug volume, and more. The full command syntax for the command is:
reduce {volume<ids>} [fit_volume] [webcut [{head|shank|both}]] [imprint] [merge][qtri] [increment_block_ids] [summary] [diameter <value>] [group_id{<value>|default}] [group_name {<string>|default}] [head_block_id{<value>|default}] [head_block_name {<string>|default}] [shank_block_id{<value>|default}][shank_block_name {|default}] [plug_block_id{<value>|default}] [plug_block_name {<string>|default}] [bolt_block_id{<value>|default}] [bolt_block_name {<string>|default}]
1.2.1.3.2 Groups Persist across Webcut
When a volume or body of a group is split in a webcut operation, the resultant pieces of the webcut will also be in the group.
1.2.1.4 Sculpt
1.2.1.4.1 HTET Unstructured Option
Sculpt now provides an option for splitting hexes into tets using an unstructured method where each hex is subdivided into six tets. Previously only the structured approach was available which split each hex into 24 tets.
1.2.1.4.2 Thicken Void
A new option for ensuring physical separation between elements of different material blocks is now provided. The new thicken_void option will insert elements designated as the void block material where non-void blocks would otherwise be in contact.
1.2.1.4.3 Better Fitting STL
Using the capture=5 option in Sculpt, mesh is fitted to the input STL. Sculpt now associates the grid edges of the reference mesh to the STL curve geometry. This is an extra level of association, in addition to the grid faces associated to the STL surface geometry. The result is better conforming of the mesh to the STL.
1.2.1.4.4 Color Smoothing Improvement
Color smoothing (spot optimization) in sculpt now extends smoothing out one additional layer of nodes after the first smoothing iteration, ensuring better quality.
1.2.1.5 Graphics, Utilities, etc.
1.2.1.5.1 Enhancements to Free Entity Selection
The ability to select free surfaces (sheet bodies) has been added to the command:
select free [surface <id_list>] [curve <id_list>] [vertex <id_list>] [add|remove]
1.2.1.5.2 No More Highlight Color Collisions
The automatic colors that Cubit assigns to entities have been slightly changed to avoid colors that are too close to the highlight color, which previously made it difficult to see what was highlighted.
1.2.1.5.3 Case Insensitive Names
When naming entities in Cubit, names are now case insensitive.
1.2.1.5.4 New HDF5 file type supported
A new file type for saving the state of the Cubit model has been introduced in Cubit 2020.2. The new file type is .cub5.
The contents and structure of the new type is exactly the same as a .trelis file, but the extension name has been changed.
Beginning with Cubit 2020.2, users will be able to read in .trelis files, .cub5 files, and .cub files.
Users will be able to export .cub files and .cub5 files, but will not be able to export .trelis files. Over time, Coreform Cubit will deprecate support for .trelis files in favor of supporting only .cub and .cub5 files.
What are the motivations for this change?
Since the brand name “Trelis” is being discontinued, retaining .trelis file extension could cause confusion
Coreform Cubit and Sandia Cubit will continue to work towards aligning the two products more closely. Currently, Sandia Cubit does not support import and export of HDF5-based model files. Adding the .cub5 file extension will enable Sandia’s support of HDF5 model files in the future.
Coreform Cubit will continue to fully support the .cub file format. A .cub file is the non-HDF5, proprietary format used by Cubit. The .cub file is freely exchanged between Coreform Cubit and Sandia Cubit assuming the underlying versions of Cubit are equivalent.
1.2.1.6 Defects Fixed in Coreform Cubit 2020.2
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1.2.1.7 Other Enhancements to Coreform Cubit 2020.2
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1.2.1.8 Limitations Introduced in Coreform Cubit 2020.2
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1.3 Release Notes: Coreform Cubit 2021.11
1.3.1 Usplines
U-splines are a revolutionary new spline technology, developed by Coreform, and can be thought of as a generalization of B-splines, NURBS, and T-splines. A U-spline is created by first generating a linear mesh to define the spline’s topology, then prescribing the polynomial degrees of the elements and degree of smoothness with their neighboring elements, and then computing the resulting U-spline in Coreform Cubit. The generated U-spline can then be used as a watertight CAD geometry definition or as an accurate and computationally efficient mesh for a simulation, a technique known as Isogeometric Analysis (IGA).
1.3.2 Usplines: Initial support in ANSYS LS-Dyna
Bézier Extraction is an IGA/spline technology that transforms a spline into a traditional "element point of view" format that can be more readily implemented in traditional finite element codes. ANSYS LS-Dyna supports Bézier extraction via DYNA’s *IGA_INCLUDE_BEZIER keyword and the "BEXT" files that Coreform Cubit can export from a U-spline.
1.3.3 Geometry Compliant Lattice Structures
Geometry Compliant Lattice Structures (GCLS) is a novel lattice construction technology that enables the efficient design of lattices that conform to a CAD model’s shape and size. GCLS structures are built using a background U-spline mesh, which the user generates on a CAD volume of the lattice region. Several default lattice unit cells are provided, as is a workflow for designing custom unit cells. This new feature is available as a separate license, Coreform Lattice GC™ . Contact sales@coreform.com for a free trial or other inquiries.
1.3.4 Updates to Coreform Cubit Learn licensing
We at Coreform are committed to ensuring that students, hobbyists, and open-source simulation developers have access to the world-class mesh generation capabilities in Coreform Cubit. In the 2020.2 release we accomplished this by releasing the Learn license for Coreform Cubit. Beginning with Coreform Cubit 2021.11, we have streamlined the licensing process for Coreform Cubit Learn. Going forward, all Cubit Learn licenses will require internet access and an account at www.coreform.com to be activated. All legacy Coreform Cubit Learn licenses that used the RLM server will expire 60 days following the release of Coreform Cubit 2021.11 (approximately January 2022).
- Get the new Coreform Cubit Learn license
Login to your Coreform account
Go to “Request Free Coreform Cubit Learn License” page
Click “Get Coreform Cubit Learn” button
- Download the latest version of Coreform Cubit
Go to Coreform Cubit Downloads page
Download the most recent release of Coreform Cubit for your platform
- Activate new Coreform Cubit Learn license
Launch latest version of Coreform Cubit
In the activation window that appears, select “Educational” and enter the email and password associated with your Coreform account
1.3.5 Changing tool for generating documentation
For many years Cubit’s help has been generated using RoboHelp. We’re transferring to using Scribble as our documentation tool, which is based on the Racket programming language. This transfer of documentation tooling, while still in its infancy, is now "live" and this manual is rendered using this new tooling. We expect there to be some rough edges, so if you find any issues with the documentation please send us a bug report at support@coreform.com!
1.3.6 Geometry tools: Taper surfaces
Exposed ACIS "taper" operation that tapers an array of faces about an array of corresponding edges and a supplied draft direction by a given draft angle.
1.3.7 Geometry tools: Create tangent curve
Added a new curve construction method that creates a spline curve that connects two points with prescribed tangent direction at each point. This can be particularly useful for smoothly connecting two discontinuous curves.
1.3.8 Mesh export: ’mesh-only’ export for ANSYS LS-Dyna
A new option has been added to the LS-DYNA .k mesh export utility to enable only writing the mesh data, which can then be *INCLUDE-d into another LS-DYNA .k file. Previously, this exporter would output a minimum working input file that included "dummy" keywords for items such as materials, steps, etc.
1.3.9 User experience: Improved performance importing complex assemblies
Improvements to file-reading algorithms have resulted in dramatically (>10x) faster performance when importing certain STEP files. For example the wall time required to read a large test file has been reduced from ~720 seconds to ~20 seconds, matching the performance of another, industry-leading, CAD software. The specific change is a refactor of the algorithm that checks for clashing entity names, turning an algorithm into an algorithm. This is not a breaking change.
1.3.10 New features in Coreform Cubit 2021.11
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1.3.11 Defects FIXED in Coreform Cubit 2021.11
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