A 3D Mouse Testimonial

The following is from an email that I received from Johnathon Wright.  I think he likes his brand new 3DConnexion Space Pilot Pro.
-David Mastel
  IT Manager
  PADT, Inc.

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top-panel-deviceRecently PADT became a certified reseller for 3Dconnexion. Shortly following the agreement a sleek and elegant SpacePilot PRO landed on my desk. Immediately the ergonomic design, LCD display, and blue LED under the space ball appealed to the techie inside of me. As a new 3D mouse user I was a little skeptical about the effectiveness of this little machine, yet it quickly has gained my trust as an invaluable tool to any Designer or Engineer. On a daily basis it allows me to seamlessly transition from CAD to 3D printing software and then to Geomagic Scanning software, allowing dynamic control of my models, screen views, hotkeys and shortcuts.

Outside of its consistency as an exceptional 3D modeling aid, the SpacePilot PRO also has a configurable home screen that allows quick navigation of email, calendar or tasks. This ensures that I can keep in touch with my team without having to ever leave my engineering programs, which is invaluable to my production on a daily basis. Whether you are a first time user who is looking to tryout a 3D Mouse for the first time or an experienced 3D mouse user who is looking to upgrade, you need to check out the SpacePilot Pro. I can’t imagine returning to producing CAD models or manipulating scan data without one. Combine the SpacePilot PRO cross-compatibility with its programmability and ease of use and you have a quality computer tool that applies to a wide range of users who are looking at new ways to increase productivity.

Link to You Tube video – watch it do its thing along with a look at my 3D scanning workstation, the GEOCUBE: http://youtu.be/fsfkLPaZJe4

Johnathon Wright
Applications Engineer,
Hardware Solutions
PADT, Inc.

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Editors Note:

Not familiar with what a 3D Mouse is?  It is a device that lets a use control 3D objects on their computer in an intuitive manner. Just as you move a 2D mouse on the plane of your desk, you spin a 3D Mouse in all three dimensions.  Learn more here

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IGES Can’t Stand IGES Anymore!

Users:

I got some errors when I imported my geometry.
I have some holes and stray surfaces in my geometry.
The edges are twisting around on my geometry import.
ANSYS blows up when I’m trying to mesh my imported geometry.

Me:

What geometry format are you using?

Users:

IGES.

IGEEEEEEESSSSSS!!!

The vast majority of the time, geometry import errors are attributable to the choice of geometry format. And that choice is IGES. To understand the problems with IGES, it helps to know a little bit of IGES history.

IGES, which stands for Initial Graphics Exchange Specification, was released in 1980 as a neutral format for sharing data between CAD systems. The most recent version, 5.3 came out in 1996.

2009_09_21_izzy

IGES: The “Izzy” of geometry formats

Besides being old, there are a few other problems with this format:

  • IGES only contains surface information. When the IGES file is read in, ANSYS has to take the additional step of creating a volume from the region enclosed by the surfaces. The IGES file contains no additional information about how the surfaces should be stitched together, so ANSYS has to figure it out, leading to possible errors, particularly with assemblies.
  • Each CAD application has its own tolerances when exporting to IGES, and loose tolerances are more likely to lead to errors in the ANSYS import.
  • Somewhat related to the previous bullet point, IGES is a middleman between the CAD system and ANSYS, creating two paths for error propagation: Exporting from CAD to the IGES file and importing the IGES file into ANSYS.

Generally speaking, IGES is typically the worst geometry format to import into ANSYS.

Now that I’ve trashed IGES, here is what I recommend:

Native Geometry

ANSYS offers several native geometry readers, such as Connections for Pro/E, NX, Solidworks, SolidEdge, etc. that bring in geometry directly from the CAD modeler. There are two advantages here:

  1. Geometry comes over directly from the CAD tool, therefore no tolerance errors propagating through a neutral geometry format “middleman.”
  2. CAD readers allow for bi-direction associativity between the CAD tool and Workbench, so a Workbench model can be refreshed to reflect updated geometry which still retaining mesh settings, loads, etc. Also, the CAD model can be refreshed based on updated geometry in Workbench.

The only catch when it comes to native geometry readers is that they require a separate license. However, about 90% of the tech support calls I’ve received about IGES import errors are from people who have licenses for native geometry readers and just aren’t using them.

Even if you have a native geometry reader license, you’ll need to be sure to check the box to install the reader during ANSYS installation. You may also need to use the CAD Configuration Manager (found in the Utilities folder in the ANSYS start menu) to configure the CAD reader if you didn’t do so during installation.

The one unfortunate exception to this is CATIA. The CATIA kernel is a bit more guarded than the other CAD kernels, and this is frequently noted in CATIA geometry import errors. Also, you can only import CATIA geometry, not associate to it as with other CAD tools.

Neutral Files That Aren’t IGES

Your ANSYS installation comes with the capabilities to import both IGES and STEP files without having to purchase an additional geometry connection license. Of the two, STEP is typically the better option. There are two reasons for this:

  1. STEP (which stands for “Standard for the Exchange of Product model data,” because these people do not bow down to society’s piddly  rules of acronym construction) contains true 3D volume definitions, instead of having to construct volumes between enclosed surface regions post-import, so the solid model definition ends up being more robust.
  2. STEP was first developed in 1984 and continues to be developed, even as recently as 2011, so export/import errors are regularly addressed, unlike with IGES.

You may also have licenses for Parasolid and/or ACIS readers, which can lead to some confusion as to which format to use. This is easily addressed by considering the underlying geometry kernel for the originating CAD tool*.

I said geometry kernel, not…oh never mind… mmmm… fried chicken….

For example, SolidEdge, NX, and Solidworks all use the Parasolid kernel. Therefore the most robust neutral format for geometry exported from these tools will generally be Parasolid (.x_t or .x_b extension), of course. Likewise, AutoCAD uses the ACIS kernel, indicating that ACIS (.sat file) will usually be the best neutral geometry format in this case. For CAD tools that use neither of these kernels, STEP will typically be the best neutral format.

As you can see, even though the IGES people know how to make acronyms, IGES is typically the last geometry format you want to try when importing or associating geometry to ANSYS. This doesn’t mean that IGES is always the worst option for reading in CAD files (especially compared to the CATIA connection), just that it usually is.

*Hat tip to Robin Steed of ANSYS, Inc. for this tip