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CUBIT Toolkit

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CUBIT 15.2 Release Notes

CUBIT 15.2 Logo
 

Product Description

New Features CUBIT 15.2

CUBIT 15.2 Documentation

Product Highlights

Limitations CUBIT 15.2

CUBIT 15.2 Contents of Release

Contact Information

Defects Fixed CUBIT 15.2

Platforms Supported

 

Known Defects CUBIT 15.2



 

Product Description

CUBIT is a full-featured software toolkit for robust generation of two- and three-dimensional finite element meshes (grids) and geometry preparation. Its main goal is to reduce the time to generate meshes, particularly large hex meshes of complicated, interlocking assemblies.

 

Product Highlights

Meshing: CUBIT is a solid-modeler based preprocessor that meshes volumes and surfaces for finite element analysis. Mesh generation algorithms include quadrilateral and triangular paving, 2D and 3D mapping, hex sweeping and multi-sweeping, tet meshing, and various special purpose primitives. CUBIT contains many algorithms for controlling and automating much of the meshing process, such as automatic scheme selection, interval matching, sweep grouping and sweep verification, and state-of-the-art smoothing algorithms.


CUBIT also includes Sculpt for automatic generation of all-hex meshes on complex parts and assemblies. Based on an overlay grid technique, Sculpt is a separate parallel executable which can be embedded directly in the analysis process for true hands-off meshing.


Mesh Scaling for Solution Verification: CUBIT includes Mesh Scaling which incrementally refines or coarsens all-hex meshes to support solution verification studies in analysis. Mesh Scaling increases or decreases the number of elements by a user-specified multiplier such as .5X, 2X, 5X, 8X, or numbers in between (rather than only an 8X multiplier as in uniform mesh refinement). This allows more solution data points to be computed using fewer hardware resources for analysis convergence studies.


Geometry Preparation: One of CUBIT's strengths is its ability to import and mesh geometry from a variety of CAD packages. CUBIT currently integrates the ACIS and Catia geometry kernels directly within its code base, allowing direct manipulation of the native CAD geometry format within CUBIT. This reduces the errors and anomalies so often associated with geometry translation. CGM (Common Geometry Module) also boasts a facet-based geometry kernel developed at Sandia that can be used for remeshing or editing old mesh files or models defined by triangle facets. In addition, CUBIT has developed a comprehensive virtual geometry capability that permits local composites and partitions to geometry without modifying the underlying native geometry representation. The user can choose to ignore, clean-up or add features to the model allowing greater flexibility to meshing algorithms to generate better quality elements.


CUBIT Environment: CUBIT has developed both a convenient command line interface with an extensive command language as well as a polished graphical user interface environment. The GUI is based upon the cross-platform standard QT, which allows the same look and feel on all supported platforms. Also included is a graphical environment based upon the VTK graphics standard which has been optimized for display and manipulation of finite element data and geometry. Fast, interactive manipulation of the model is a tremendous advantage for models with thousands of parts or millions of elements.


For more information on CUBIT, including licensing arrangements and terms see the CUBIT website http://cubit.sandia.gov

 

New Features in CUBIT 15.2

Index of New Features

 

Meshing

 

Adaptive Refinement with Sculpt

Sculpt Scalability Improvements

Selective Hexahedral Mesh Scaling

Improved Sideset/Nodeset/Block Support in Hexahedral Mesh Scaling

 

Geometry

 

Volume Metric with Extended Command Line Entity Specification

 

Import/Export

 

Exodus Attributes

Pyramid Support in Nastran Exporter

 

Graphics, Utilities, etc.

 

Info Messages and Logging File

Software Development Kit (SDK)

 



Meshing


Adaptive Refinement with Sculpt


Sculpt is a companion application to CUBIT that enables hands-off all-hex meshing of complex models. A new adapt capability in version 15.2 automatically detects small features and curvature in the geometry and generates smaller elements in those regions. The capability uses an automatic 2-refinement procedure where cells in the base Cartesian grid are split into 8 sub-cells. The refinement repeats recursively until a maximum number of refinement levels is reached or a user-defined adapt threshold is achieved. The following images show the effect of 4 levels of adaptive refinement in a Sculpt mesh of a single mechanical part.

Sculpt Adaptive Refinement

Sculpt Adaptive Refinement

The sculpt parallel command in CUBIT includes new options to exercise the adaptivity capability:


sculpt parallel [options...] [adapt_type <value>] [adapt_levels <value>] [adapt_threshold <value>]



Sculpt Scalability Improvements


Version 15.2 includes performance enhancements that permit Sculpt hex meshing on problems with 10s or 100s of material blocks. This capability is especially helpful for meshing microstructure models where individual grains are represented by independent materials. The image below shows an example where 75 separate materials are used. Where previously it would take hours to run, this model now runs in only a few seconds. The enhancements are also applicable to general STL input allowing for many more materials to be meshed in the same run.

Sculpt Adaptive Refinement

Selective Hexahedral Mesh Scaling


Mesh Scaling has been enhanced to allow selective scaling of the model by entering a list of the desired volumes to scale. The updated command syntax is:


Scale Mesh [volume <ids>][Multiplier <value>] [minimum <value>] [{SWEPT_BLOCKS|structured_blocks}] [feature_angle <value>] [force_structured in {[volume <ids>] [surface <ids>]}]


Mesh Scaling will scale the mesh in the specified volumes as well as any other non-specified volumes which are connected to the specified volumes through merged geometry. This allows the user to easily scale the mesh in one assembly component, leaving the rest of the mesh unchanged.


Improved Sideset/Nodeset/Block Support in Hexahedral Mesh Scaling


Mesh Scaling has been enhanced to better support blocks, sidesets, and nodesets. Just like in previous releases, any block, sideset, or nodeset that is defined by specifying geometric entities will continue to be honored by mesh scaling. New to this release is better support for blocks, sidesets, and nodesets defined by specifying mesh entities. For example, the mesh below has a sideset defined explicitly with 2 quad faces. In CUBIT 15.1, the quad faces are honored explicitly and not changed, creating a zone of the mesh that is not scaled. In CUBIT 15.2, the boundary of the sideset is maintained by mesh scaling and the number of faces inside of the sideset is scaled along with the rest of the mesh.


Mesh Scaling Sidesets


Nodesets and Blocks are now handled in a similar manner. The mesh below has a nodeset defined explicitly with 6 nodes. In CUBIT 15.1, the nodes in the nodeset are honored exactly as hardpoint constraints in mesh scaling. In CUBIT 15.2, the boundary of the nodeset is maintained and the number of nodes inside the nodeset is scaled along with the rest of the mesh.


Mesh Scaling Nodesets


For Blocks, in CUBIT 15.1 when the hexes in the model are deleted before remeshing, any blocks defined by hex elements would be left empty. In CUBIT 15.2, the boundary of the block is maintained and the number of elements inside the block is scaled along with the rest of the mesh.




Geometry


Volume Metric with Extended Command Line Entity Specification


The volume of a Volume Entity may now be used with the extended command line entity specification. This is similar to the existing capability to select curve entities based on length, or surface entities based on area. The following is an example of a command using the new volume metric.


group "_brackets" add volume with volume >= 4 or with volume = 1




Import/Export


Exodus Attributes


In previous versions of CUBIT, default attributes would be provided for some element types at export time. This included SPHERE, BAR, BEAM, TRUSS and SHELL. For other element types, CUBIT would not create default attributes. Now, for consistency, Cubit will not create default attributes for any element types.

Users previously relying on default attributes may now need to specify the attribute count using the command

block <id> attribute count <count>


Pyramid support in Nastran


The Nastran exporter in CUBIT has been enhanced to support pyramid elements.




Graphics, Utilities, etc.


Info messages and logging file


Independent control of information and warning messages into a logging file has been added. For example, to get information messages in a logging file but no information messages in the application window, one may do

set logging on file 'log.txt'
set info off
set info on logging



Software Development Kit (SDK)


CUBIT now provides a Software Development Kit (SDK) for 3rd party developers. This SDK provides a plugin interface that allows 3rd party developers to access internal CUBIT functionality. The access is allowed through a set of well defined interfaces. These interfaces allow users to access the CUBIT command structure so that they can:

1. Add custom commands
2. Access the geometry engine to query and modify geometry
3. Export mesh data to your custom data
4. Import mesh data into CUBIT from your custom data
5. Query CUBIT state information.

Documentation and example plugins are included in the SDK package. The SDK is packaged in a separate download. Contact cubit-help@sandia.gov for access to the SDK.


Limitations in CUBIT 15.2


No known limitations.  


Fixed Defects in CUBIT 15.2


The following items are the user-reported bugs fixed since last release of CUBIT. For more information contact Byron Hanks at (cubit-support@sandia.gov).


Ref #

Resolved Defect*

11548

Crash in Mesh->Curve->Mesh Command Panel

11550 Crash - invalid MBG created importing MBG with hardpoints
11560 Cubit Is Busy Error
11576 Error opening .cub file: ": Got more geometry entities during geometry import than expected. Aborting - mesh not restored."
11621 Save/restore error - more geometry entities than expected.

 

*The defects listed above are only those user-reported issues deemed "critical" or "blocker". For information on other resolved defects contact Byron Hanks.

 

Known Defects in CUBIT 15.2


No known critical or blocker defects.

 

Documentation Updates


The CUBIT 15.2 online documentation may be found here. Both a PDF version and a Microsoft Word version are also available for download. The CUBIT GUI installation also includes the full user documentation included with the program. The user's manual may be accessed from the Help menu.

CUBIT 15.2 Contents of Release


CUBIT Program
: The installation package includes executables and libraries packaged in tar.gz files for Linux machines. For Windows, the package is in a self-installing executable, and for Mac OS X a .dmg file is provided. Both a command line and GUI version of CUBIT are included with the installation package for all platforms.


Documentation: Linux, Windows and Mac versions include full online documentation. Windows also includes .chm (Windows Help File), of the complete documentation that can be run separately from CUBIT.


 

Platforms Supported


CUBIT 15.2 supports the following Platforms:


  • Linux RedHat Enterprise 6, 64-bit

  • Windows 7, XP, Vista, 64-bit

  • Mac OS X Intel based (10.9)


Non-Sandia Users

CUBIT is freely available for United States government use. For more information on licensing CUBIT, including academic, commercial, and all other use, go to our licensing page. For current CUBIT users, CUBIT 15.2 may be downloaded from the CUBIT download page.

Sandia Personnel Only

CUBIT 15.2 may be downloaded from the CUBIT download page.
Windows
Download a Windows installation file and double-click to install.
MAC OS X
Download a Mac OS X disk image file. After the disk image is opened, click and drag the Cubit folder to /Applications.
LINUX LANS
Check with your local LAN administrator for instructions on how to access CUBIT on your local LAN. In most cases typing one of the following commands at the UNIX prompt should allow you to execute CUBIT.  In some cases, the full path will need to be specified:
/projects/cubit/<cubit_command>

cubit

The latest released 64-bit version (15.2) of CUBIT deployed to the LAN.

cubit -nogui

The latest released 64-bit version (15.2) with just the Command Line and graphics window

cubit -nogui -nographics

The latest released 64-bit version (15.2) with just the Command Line

cubit-15.2

64-bit Version 15.2 with GUI

cubit-beta

The latest beta version still in development

 

Contact Information


CUBIT Help

For general technical questions including download, installation and CUBIT technical assistance.
cubit-help@sandia.gov

CUBIT Licensing and Passwords

Ariana Rossi
Cubit Licensing
Email: Cub-Req@sandia.gov

CUBIT Support Lead

Clint Stimpson
Cubit Support Lead
Email: cubit-support@sandia.gov

CUBIT Project Lead

Byron Hanks
Sandia National Laboratories
Computational Simulation Infrastructure (org. 1543)
Email: cubit-support@sandia.gov

Web site contact: Cubit Support