CUBIT 10.2 Release Notes

Product Description

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 also includes state-of-the-art smoothing algorithms.

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 geometry kernel directly within its code base, allowing direct manipulation of the ACIS native CAD geometry format within CUBIT. This reduces the errors and anomalies so often associated with geometry translation. CGM 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 CUBIT 10.2

CUBIT 10.2, released October 2006, incorporates the following new features:

	Meshing		Geometry		GUI		Properties and Support
Improved Sweeping Algorithms Auto mesh sizing defaults Enhanced Spider command		Interoperable Virtual Geometry Enhanced Midsurface capability ACIS Upgrade (V16) Granite (Pro/E) on Linux		New Mesh Quality Power Tool Enhanced Mesh Power Tool Customizable Tool Buttons Overlapping Surface check New Mesh scheme and sizing panels Patran , Ideas, Abaqus import/export dialogs Enhanced mesh sizing panel DART Metadata global values Display Working Directory		Variable distribution factors Optional Nodemap Abort management Tip of the Day Help Buttons Composite surfaces visualization Background Gradient Color Alpha Features New Installation Package

Meshing

Improved Sweeping Algorithms

One of CUBIT's key strengths is it's ability to produce an all-hexahedral mesh using the sweeping algorithm. This release has included substantial work on the core sweeping algorithm. In particular, the sweeping kernel has been componentized and is available as a separate component in the CAMAL library, which is also incorporated into CUBIT. In the process, the sweeping algorithm has been made more efficient, in some cases speeding up meshing times by as much as 40%.

Auto mesh sizing defaults

CUBIT provides the ability to automatically define a variable mesh size based upon geometric properties of the model. The default parameters for the automatic mesh sizing have been changed to reflect common usage patterns. These parameters can also be manually adjusted using the mesh sizing command panels.

Enhanced Spider command

The Spider command provides the ability to create one or more beam elements from a single node or vertex to one or more nodes located on a surface or element face. Previous versions of CUBIT would generate a separate geometric curve entity for each bar element created. CUBIT 10.2 will only generate the bar elements without geometry.

Back to New Features

Geometry

Interoperable Virtual Geometry

CUBIT has a powerful virtual geometry engine that enables the user to change the topology of a CAD model by compositing, partitioning or collapsing entities without changing the underlying solid model. Up until now, any real geometric operations, such as webcut and imprint had to be done prior to any virtual operations. In most cases, in order to effectively use virtual geometry, the user had to carefully plan the order in which operations were performed, leaving virtual operations until the end. CUBIT 10.2 reduces the restrictions on the order of virtual and real operations. In particular, webcut and imprint operations can be performed on entities that have been previously been composited. This makes CUBIT's virtual geometry capability much more flexible, enabling the user to combine real and virtual operations to achieve results faster.

Enhanced Midsurface capability

CUBIT 10.1 introduced a limited midsurface capability that supported creation of surfaces between planar and co-axial analytic surfaces. CUBIT 10.2 enhances this capability to be able to handle any quadric surface and permitting parallel axis analytics.

ACIS Upgrade (V16)

ACIS is the third party geometry kernel that serves as the basis for all geometric operations in CUBIT. CUBIT 10.2 includes an upgraded version of ACIS to version 16.1. This may have some effect on the resulting entity IDs that are generated as a result of geometric operations between version 10.1 and 10.2 of CUBIT. Although the ID changes are minimal, if old journal files fail to run because of ID changes, we recommend using the ID-Less journal file capability to upgrade your old journal files to be compatible with version 10.2.

Granite (Pro/E) on Linux

The Granite geometry kernel, introduced in CUBIT 10.0 is an optional library that is built on the same geometry kernel as PTC's Pro Engineer product. Up until now, only Windows, SUN and SGI versions of Granite have been available from PTC. PTC has now made available a Linux version of Granite which has been incorporated into CUBIT 10.2. This permits Pro/E users access to the full capability of Cubit on Linux systems using Pro/E native geometry.

Back to New Features

GUI

New Mesh Quality Power Tool

Enhanced Mesh Power Tool

Customizable Tool Buttons

The capability to add custom buttons to the GUI has been added in CUBIT 10.2. A set of user defined commands can be assigned and buttons created that will be displayed in a toolbar. This new feature is useful for creating macros or executing a set of commonly used commands. To create new custom buttons, go to the Tools menu and click on Options; then select Custom Tools from the list at the left.

Overlapping Surface check

	One of the most common errors for novices and experienced users alike is to forget to merge parts of an assembly together before meshing. Without a correctly merged model, a contiguous mesh cannot be created. This error is sometimes not detected until after the mesh has been exported and used for analysis. The meshing panel now includes the option to check for overlapping surfaces before meshing.
If overlapping surfaces are detected, a message will be displayed allowing the user to continue or to stop the meshing process. On large models the overlapping surface check can take some time to complete, so the user has the option to turn this feature off.

New Mesh scheme and sizing panels

In previous versions of CUBIT, both the mesh sizing and meshing schemes were set from the same command panel. In CUBIT 10.2, in order to simplify and clarify these operations, they have been separated into two panels. The meshing operation can be performed from both of these panels.

Patran, Ideas, Abaqus import/export dialogs

GUI Dialogs to support import and export of Patran, Ideas and Abaqus files have been added. Previously this capability was only available from the command line.

Enhanced mesh sizing panel

The geometry-adaptive mesh sizing meshing panel now provides the ability to modify the maximum and minimum mesh sizes as well as control of the maximum gradient size directly from the top level geometry-adaptive mesh sizing panel.

DART Metadata global values

The ability to create and modify DART Metadata was added in recent versions of CUBIT. Some global attributes that are not specifically associated with a part or sub-assembly could not be set from the GUI. By clicking on the top level "Assembly" icon in the geometry tree, the property panel now displays the current global Metadata values which can be edited directly in the panel.

Display Working Directory

The current working directory is now displayed at the bottom of the CUBIT window. This is the default directory where files are written or opened.

Back to New Features

Properties and Support

Variable distribution factors

Distribution factors are values defined in the Exodus II specification usually associated with a nodeset. These values, often representing a physical load or initial condition can now be defined using an equation. CUBIT 10.2 now provides the capability to define a general equation that can be assigned to a nodeset.

Optional Nodemap

The Exodus II specification provides the option to define a node map. A node map defines how the finite element nodes will be numbered once they are written to the file. By default, CUBIT will include a node map in the exodus file, however some analysis codes do not support the node map option or make different assumptions regarding its use. Therefore, CUBIT 10.2 now provides an option to turn off the nodemap information in the exodus file.

Abort management

Unexpected aborting of the program can sometimes cause significant loss of time and effort. While the Cubit team makes every effort to clear up code defects that can cause an abort, on rare occasions, they will occur. To help minimize the effects of program aborts, CUBIT 10.2 will automatically attempt to write the current model database to a .cub file.

Tip of the Day

CUBIT contains hundreds of commands and options, all oriented to getting the geometry and meshing task done in a fast and efficient manner. To effectively learn these commands and take advantage of them to improve productivity can be an overwhelming task. CUBIT 10.2 now provides a Tip-of-the-Day mechanism which is displayed at start-up. These contain the most valuable commands and procedures collected from expert users to help do common tasks and improve productivity. This mechanism can be turned off at start-up, but also can also be accessed from the Help menu.

Help Buttons

New help buttons have been incorporated into all of the CUBIT command panels. Selecting one of these buttons will display the CUBIT help system with information about the relevant operation.

Composite surfaces visualization

CUBIT provides the capability to composite adjacent surfaces. In previous versions of CUBIT, the composited representation appeared as a single surface with no indication of the common curves. CUBIT 10.2 now displays these curves as dotted lines. A new toolbar button in the Display Tools will toggle the appearance of virtual curves.

Background Gradient Color

CUBIT 10.2 now provides the capability to choose a background based on two colors. The background may have a smooth color gradient from the selected top color to the bottom color. The selected colors will be maintained between restarts of the program. To change the background colors go to the Display menu and select Background.

Alpha Features

For many years, CUBIT has had a strong research component, serving as a platform for cutting edge technical advancements in geometry and meshing. At the same time it serves as a day-to-day software tool for engineers and analysts. Many of the research features, although still under development, are made available in the CUBIT software. In order to better manage these features, CUBIT 10.2 now incorporates a new mode which allows access to research tools. To access this mode, use the following command from the CUBIT command line

set developer ON|OFF

The following is a list of commands which are now only available if the developer flag has been set to ON.

Although extremely useful in many situations, these commands are designated as research. Use of these commands should be done with caution and with the understanding that they are not fully tested and intended for regular use.

At times, commands will be deprected from the code base, when in spite of their long history in Cubit they become to difficult to maintain and of marginal use. In version 10.2, the following meshing schemes have been removed from the code and documentation:

• hextet
• hextovoid

New Installation Package

In previous versions of Cubit, a separate download was required for both command line and GUI versions. The new installation package for all platforms now include both versions in the same install. Since both versions utilize the same core libraries, there was a relatively small overhead size to the installation package by including both.

Back to New Features

 

Limitations CUBIT 10.2

• Compaq Alpha and HPUX CUBIT platforms are not supported in CUBIT 10.2. Previous versions of these platforms will continue to be made available from the CUBIT downloads site.
• The new Granite Geometry Kernel is currently not supported on Mac OS. As of this release, PTC has not announced plans to support a Mac OS version of Granite.
• The Granite Kernel supports most of the commands and options used with the standard ACIS implementation in CUBIT. See the Granite document in the users manual for a description of differences between the CUBIT's supported options between Granite and ACIS.
• The Mac OS X port does not support the changing mouse cursors on pre-selection
• It is recommended that a 3-button mouse be used for the Mac OS X version since interactive transformation utilize all three buttons.

Defects Fixed in CUBIT 10.2

The following items are the user-reported bugs fixed since last release of CUBIT (March 2006). For more information contact Kevin Pendley (kpendle@sandia.gov)

Known Defects CUBIT 10.2

The following items are bugs or limitations that may be encountered in the current release of CUBIT. For more information on these defects or to report additional defects contact Kevin Pendley (kpendle@sandia.gov)

Documentation Updates

CUBIT 10.2 How To

CUBIT 10.2 Contents of Release

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

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

Platforms Supported

CUBIT 10.2 supports the following Platforms

• Linux RedHat 9.0 32- and 64-bit
• SGI Irix 6.5 32- and 64-bit
• Sun Solaris 8
• Windows 2000, XP
• Mac OS X

Non-Sandia Users

CUBIT is available to for government and academic use. For information on licensing CUBIT go to the follow URL: http://cubit.sandia.gov/licensing.html. For current CUBIT users, CUBIT 10.2 may be downloaded from the website at the following URL: http://cubit.sandia.gov/downloads.html. If you obtained a password since the release of CUBIT 10, your paswoord should work for 10.2 also.

Sandia Personnel Only

Windows

Download a Windows installation file from the dropzone. Go to the following directory \\dropzone\public\cubit\Windows. Copy the file Cubit.WindowsGUI.10.2.exe to your windows hard drive. Double click on the file and follow the installation instructions.

MAC OSX

Download a Mac OSX disk image file from the dropzone. Go to the following directory \\dropzone\public\cubit\MAC_OS_X. Copy the file Cubit_GUI_10.2.dmg.gz to your mac harddrive. Use gunzip to unpack the disk image file.

UNIX/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:

Contact Information

CUBIT Help

For general technical questions including download, installation and CUBIT technical assistance.

cubit-help@sandia.gov

CUBIT Licensing and Passwords

Lydia Koch
Cubit Licensing
Phone: 505-284-1783
Email: lkkoch@sandia.gov

CUBIT Support Lead

Kevin Pendley
CUBIT Support Manager
Phone: 505-284-1957
Email: kpendle@sandia.gov

CUBIT Project Lead

Steven J. Owen
Sandia National Laboratories
Computational Modeling Sciences Department (org. 1421)
Phone: 505-284-6599
Email: sjowen@sandia.gov