Configuring Laptop “Switchable” Graphics for ANSYS Applications


A lot of laptops these days come with “switchable” graphics.  The idea is that you have a lower capability but also lower power consuming ‘basic’ graphics device in addition to a higher performing but higher power demand graphics device.  By only using the higher performance graphics device when it’s needed, you can maximize the use time of a battery charge. 

A lot of the ANSYS graphics-intensive applications may need the higher end graphics device to display and run correctly.  In this article, we’ll focus on the AMD Firepro as the “higher end” graphics, with Intel HD graphics as the “lower end”.  We will show you how to switch to the AMD card to get around problems or errors in displaying ANSYS user interface windows.

The first step is to identify the small red dot graphics icon at the lower right in the task bar:


Figure 1 – AMD Catalyst Icon


Next, right click on the icon to bring up the AMD Catalyst Control Center, if you don’t see the switchable option as shown two images down.


Figure 2 – AMD Catalyst Control Center Right Click Menu Pick


Right click on the same icon again, if needed to select “Configure Switchable Graphics,” as shown here:


Figure 3 – Select “Configure Switchable Graphics” via Right Click on the Same Icon


In the resulting AMD Catalyst Control Center window, click on the Add Application button.


Figure 4 – AMD Catalyst Control Center Window

Next browse to the application that needs the higher end graphics capability.  This might take a little trial and error if you don’t know the exact application.  Here we select ANSYS CFD-Post and click Open.


Figure 5 – Selecting appropriate executable for switchable graphics

Finally, select the High Performance option from the dropdown for your chosen executable, then click the Apply button.


This should get your graphics working properly.  Again, the reason we have the two graphics choices is to allow us to better control power consumption based on the level of graphics that are needed per application.  Hopefully this article helps you to choose the proper graphics settings so that your ANSYS tools behave nicely on your laptop.

Getting to know ANSYS – SIwave

This video is an introduction to ANSYS SIwave – an analysis tool for Integrated Circuits and PCBs

Checking Hyper-Elastic Material Models

non-linear-thumbWhen using hyper-elastic materials, analyst often have little material data to assist them. Fortunate engineers will have a tensile stress-strain curve; a lucky few will also have a simple shear stress-strain curve as well. Where do you start?

To gain confidence in the procedure which is typically used, a set of FEA models were run in a closed loop. The loop consists of assuming some material parameters, running FEA models based upon those parameters, and then using the FEA results to recover the material parameters using ANSYS’s built in hyper-elastic curve fitting.

To isolate the material model from boundary conditions effects, simple FEA models that are 3D but have 1D stress states are used. The figures below show tensile and shear models that can be used to verify material models.

For this article, a 2 Parameter Mooney-Rivlin material model with values consistent with typical Imperial units was selected. The figure below shows the data entry including a value of zero for d which indicates that the material is fully incompressible.

The tensile test FEA model was run with this 2 parameter MR model. The engineering stress-strain results were extracted from the results using /post26 APDL. The results are graphed and listed in the figure below. We use APDL because there are some calculations involved with getting engineering results. For example, the engineering stress was calculated by dividing the reaction force at node n1 by the original area like this:

QUOT,3,2, , , , , ,-1/area_,1,

cs3This test data was then used in ANSYS’s curve fitting routine. The results of the curve fitting are shown below. The parameters from the curve fitting results are < 0.01% different than the assumed inputs. This is a reassuring result. Note that this is one instance in ANSYS that you are required to use engineering data (for hyper-elastic curve fitting only).

In recent versions of ANSYS, a hyper-elastic response function was introduced. This allows the user to enter the test data and use it without curve fitting. The figure below shows how uniaxial tension test data is entered and the response function activated to use it.

As expected, the response function matched the /post26 output exactly. This method offers a clear advantage in that the user doesn’t need to assume a material model.

The next step in this verification process was to run some simple shear FEA models to compare the curve fitting results. The plot below shows the engineering shear stress-strain curve using the 2 parameter MR model from above.

The data was curve fitted as shown in the figure below. This time both the uniaxial tension and simple shear data are entered. The resulting 2 parameter model differs (<2%) from the entered model.

These new values were used in the FEA models. As shown in the figures below, the change in material parameters (<2%) did not significantly change the tensile or shear stress-strain results (<1%). This raises some interesting questions regarding the 2 parameter MR model that will be explored at a later date.

You will be Surprised Where Sneeze Germs Travel in an Airplane

sneezing-in-airplane-300x279Ever been on a flight, hear someone sneeze, and then sit in fear as you imagine millions of tiny infectiousness germs laughing historically as they spread through the cabin of the plane?  In my imagination they are green and drip mucus. In reality they are small liquid particles and instead of going everywhere, it appears they fall on just a few unlucky people. 

ANSYS, Inc.  put out a very cool video showing the results of an in-cabin CFD run done by Purdue University that tracks the pathogens as they leave the sick persons mouth, get caught in the climate control system’s air stream, and waft right on the people next to and behind them.  The study was done for the FAA Center for Excellence for Airliner Cabin Environment Research.   

Here is the video, check it out and share with your friends. Especially if you have a friend that doesn’t sneezes out into the open air:

Visit the ANSYS Blog to learn even more.


Continue a Workbench Analysis in ANSYS MAPDL R15

stopsignThis article outlines the steps required to continue a partially solved Workbench based analysis using a Multi-Frame Restart and the MAPDL Batch mode.

In this article you will learn:

  • Some ways to interface between ANSYS Workbench and ANSYS MAPDL
  • How to re-launch a run using a Multi-Frame Restart in ANSYS Batch mode
  • The value of the jobname.abt functionality for Static Structural and Transient Structural analyses

Recently I was working in the ANSYS Workbench interface within the Mechanical application running a Transient Structural analysis. I began my run thinking that my workstation had the necessary resources to complete the analysis in a reasonable amount of time. As the analysis slowly progressed, I began to realize that I needed to make a change and switch to a computer that had more resources. But some of my analysis was already complete and I did not want to lose that progress. In addition, I wanted to be sure that I could monitor the analysis intermediately to ensure that it was advancing as I would like. This meant that however I decided to proceed I needed to make sure that I could still read my results back into Mechanical along with having the capability to restart again from a later point. Here were my options.

1: I could use the Remote Solve Manager (RSM) to continue running my analysis on a compute server machine. Check out this article for more on that.

I did use RSM in part but perhaps you do not have RSM configured or your computer resources are not connected through a network. Then I will show the other option you can use.

2: A Multi-Frame Restart using MADPL in ANSYS Batch mode

Here’s the process:

1. Make note of the current load step and last converged substep that your analysis completed when you hit the Interrupt Solution button

2. Copy the *.rdb, *.ldhi, *.Rnnn files from the Solver Files Directory on the local machine to the Working Directory on the computing machine

You can find your Solver Files Directory by right clicking on the Solution Branch in the Model Tree and selecting Open Solver Files Directory:

3. Write an MAPDL input file with the commands to launch a restart and save it in the Working Directory on the computing machine (save with extension *.inp)

Below is an example of an input that will work well for restarting an analysis, but feel free to adjust it with the understanding that the ANSYS Programming Design Language (APDL) is a sophisticated language with a vast array of capability.

4. Start the MADPL Product Launcher interface on the computing machine and:
    a: Set Simulation Environment to ANSYS Batch
    b. Navigate to your Working Directory
    c. Set the jobname to the same name as that of the *.rdb file
    d. Browse to the input file you generated in Step 3
    e. Give your output file a descriptive name
    f. Adjust parallel processing and memory settings as desired
    g. Run


5. Look at the output file to see progress and monitor the run

6. Write “nonlinear” in a text file and save it as jobname.abt inside the Working Directory to cleanly interrupt the run and generate restart files when desired

The jobname.abt will appear briefly in the Working Directory

The output file will read the following:

Note that the jobname.abt interruption process is the exact process that ANSYS uses in the background when the Interrupt Solution button is pressed interactively in Mechanical

Read more about the jobname.abt functionality in the Help Documentation links at the end of this article.

7. Copy all newly created files in Working Directory on the computing machine to the Solver Files Directory on the local machine

8. Back in the Mechanical application, highlight the Solution branch of the model tree, select Tools menu>Read Results Files… and navigate to the Solver Files Directory and read the updated *.rst file

After you have read in the results file, notice that the restart file generated from the interruption through the jobname.abt process appears as an option within the Mechanical interface under Analysis Settings

9. Review intermediate results to determine if analysis should continue or if adjustments need to be made

10. Repeat entire process to continue analysis using the new current loadstep and substep

Happy solving!

Here are some useful Help Documentation sections in ANSYS 15 for your reference:

  • Understanding Solving:
    • help/wb_sim/ds_Solving.html
  • Mechanical APDL: Multiframe Restart:
    • help/ans_bas/Hlp_G_BAS3_12.html#BASmultrestmap52199

And, as always, please contact PADT with your questions!

Video Tips: Create and Display Custom Units in ANSYS CFD-Post

By: Susanna Young

ANSYS CFD-Post is a powerful tool capable of post-processing results from multiple ANSYS tools including FLUENT, CFX, and Icepak. There are almost endless customizable options in ANSYS CFD-Post. This is a short video demonstrating how to create and display a set of custom units within the tool. Stay tuned for additional videos on tips for more effective post-processing in ANSYS CFD-Post.

ANSYS Remote Solve Manager (RSM): Answers to Some Frequently Asked Questions

rsm-1For you readers out there that use the ANSYS Remote Solve Manager (RSM) and have had one or all of the below questions, this post might just be for you!

  1. What actually happens after I submit my job to RSM?
  2. Where are the files needed to run the solve go?
  3. How do the files get returned to the client machine, or do they?
  4. What if something goes wrong with my solve or in the RSM file downloading process, is there any hope of recovery?
  5. Are there any recommendations out there for how best to use RSM?

If your question is, how do I setup RSM as a user? You answers are here from a post by Ted Harris. The post today is a deeper dive into RSM.

The answers to questions 1 through 3 above are really only necessary if you would like to know the answer to question 4. My reason for giving you a greater understanding of the RSM process is so that you can do a better job of troubleshooting should your RSM job run into an issue.  Also, please note that this process is specifically for an RSM job submitted for ANSYS Mechanical. I have not tested this yet for a fluid flow run.

What happens when a job gets submitted to RSM?

The following will answer questions 1-3 above.

When a job is run locally (on your machine), ANSYS uses the Solver Files Directory to store and update data. That folder can be found by right clicking on the Solution branch in the Model tree and selecting Open Solver Files Directory.

The project directory will be opened and you can see all of the existing files stored for your particular solution:

When a job gets submitted to RSM, the files that are stored in the above folder will be transferred to a series of two temporary directories. One temporary directory on the client side (where you launched the job from) and one temporary directory on the compute server side (where the numbers get crunched).

After you hit solve for a remote solve, you will notice that your project solver directory gets emptied. Those files are transferred to a temporary directory under the _ProjectScratch directory:
p3 p4

Next, these files get transferred to a temporary directory on the compute server. The files in the _ProjectScratch directory will remain there but the folder will not be updated again until the solve is interrupted or finished.

You can find the location of the compute server temporary directory by looking at the output log in the RSM queueing interface:

If you navigate to that directory on your compute server, you will see all of the necessary files needed to run. Depending on your IT structure, you may or may not have access to this directory, but it is there.

Here is a graphical overview of the route that your files will experience during the RSM solve process.

Once your run is completed or you have interrupted it to review intermediate results and your results have been downloaded and transferred to the solver files folder, both of the temporary directories get cleaned up and removed. I have just outlined the basic process that goes on behind the scenes when you have submitted a job to RSM.

What if something goes wrong with my RSM job? Can I recover my data and re-read it into Workbench?

Recently, I ran into a problem with one of my RSM jobs that resulted in me losing all of the data that had been generated during a two day run. The exact cause of this problem I haven’t determined but it did force me to dive into the RSM process and discover what I am sharing with you today. By pin-pointing and understanding what goes on after the job is submitted to RSM, I did determine that it can be possible to recover data, but only under certain circumstances and setup.

First, if you have the “Delete Job Files in Working Directory” box checked in the compute server properties menu accessed from the RSM queue interface (see below) and RSM sees your job as being completed, the answer to the above question is no, you will not be able to recover your data. Essentially, because the compute server is cleaned up and the temporary directory gets deleted, the files are lost.

To avoid lost data and prepare for such a catastrophe, my recommendation is that you or your IT department, uncheck the “Delete Job Files in Working Directory” box. That way, you have a backup copy of your files stored on the server that you can delete later when you are sure you have all of your files safely transferred to your solver files folder within your project directory structure.

The downside to having this box unchecked is that you have to manually cleanup your server. Your IT department might not like, or even allow you to do this because it could clutter your server if you do not stay on top of things. But, it could be worth the safety net.

As for getting your data back into Workbench, you will need to manually copy the files on the compute server to your solver files folder in your Workbench project directory structure. I explained how to access this folder at the beginning of this post. Once you have copied those files, back in the Mechanical application, with the Solution branch of your model tree highlighted, selects Tools>Read Results Files… (see below graphic), navigate to your solver files directory, select the *.rst file and read it in.

Once the results file is read in, you should see whatever information is available.


  • Though it is possible to run concurrent RSM jobs from the same project, my recommendation is to only run one RSM job at a time from the same project in order to avoid communication or licensing holdups

  • Unless you are confident that you will not ever need to recover files, consider unchecking the “Delete Job Files in Working Directory” box in the compute server properties menu.

    • Note: if you are not allowed access to your compute server temporary directories, you should probably consult your IT department to get approval for this action.

    • Caution: if you uncheck this box, be sure that you stay on top cleaning up your compute server once you have your files successfully downloaded

  • Depending on your network speed, when your results files get large, >15GB, be prepared to wait for upload and download times. There is likely activity, but you might not be able to “see” it in the progress information on the RSM output feed. Be patient or work outside of RSM using a batch MAPDL process.

  • Avoid hitting the “Interrupt Solution” command more than once. I have not verified this, but I believe this can cause mis-communication between the compute server and local machine temporary directories which can cause RSM to think that there are no files associated with your run to be transferred.


PADT Opens Utah Office

PADT-UtahIt is now official: PADT has an office in the Salt Lake City area, second after the class A office space in Austin, TX.  Last week we signed a lease for a space at 5282 S Commerce Dr in Murray, Utah.  We have been looking for a while and when this location opened up we felt it was located in a great spot and was the size we needed.  It is 17 minutes from downtown Salt Lake City, less than 30 minutes to most of our SLC customers, and not a bad drive to those who are north and south, right up or down I-15.

This office will focus on providing sales and technical support to our Utah Stratasys and ANSYS customers.  It will provide enough space for a few demo 3D Printers and also has a great meeting room for training and mentoring sessions.

You can read more in the official press release here.  

To get a feel for where it is located, here is a screen grab.


Proximity to some of the best skiing in the country was not much of a factor in the decision process… but it helped.

Here is a shot of Anthony, Doug, Patrick, and Mario modeling in the hallway. 


It will take us a month or so to get everything up and running, but once done we will set up a time for an open house. Watch this space for more about our continued growth and success in Utah.

Video Tips: Using ACT to change Default Settings in ANSYS Mechanical

A short video showing how ACT (ANSYS Customization Toolkit) can be used to change Default Settings for analyses done in ANSYS Mechanical.  This is a very small subset of the capabilities that ACT can provide.  Stay tuned for other videos showing further customization examples.

The example .xml and python file is located below.  Please bear in mind that to use these “scripted” ACT extension files you will need to have an ACT license.  Compiled versions of extensions don’t require any licenses to use.  Please send me an email ( if you are wondering how to translate this example into your own needs.


Video Tips: Workflow for Designing Electric Motors in ANSYS

A quick video showing you a great workflow for designing electric motors. It shows going from a quick template based design tool to a full 3D analysis tool

Recommended Free Utilities for the ANSYS User’s Toolbox

free-stuffWhat do you have in your toolbox? The ANSYS suite of tools is pretty comprehensive.  But an efficient user always has a collection of utilities that they use with ANSYS products to automate processes, convert data, and scrub results.  In 2008 we published a list of free and commercial tools that we were using at PADT, and web results show that it is one of our more popular posts. So we thought it was a good time to revisit and update those lists.

We will start with the free tools, well because everyone loves something for free. This is by no means a comprehensive list, these are simply the tools we currently use here at PADT. If you have alternative suggestions, please leave them in a comment.  I tried to put them in some logical grouping, but failed.  So here they are, in no particular order:

untitled python
Scripting Language

Every good simulation user needs scripting.  We spend a lot of time dealing with large amounts of data and setting up all sorts of complicated processes.  Scripting can be used to create, modify, sift through, or translate text versions of our models, loads, and results.  Some users like to stick with APDL and never leave ANSYS, some know Matlab very well.  Others may use newer languages like Lua or older ones like perl.
Here at PADT we have found that python is the best tool for scripting outside of ANSYS MAPDL (we use APDL if we are in the program).  Not only is it easy to learn and use, it has hundreds of free libraries that do almost anything you want. Lots of people know it, and you are not dependent on some other piece of software. Python also works on Linux and Windows. In addition, most CAE tools these days support python scripting.  This is certainly true of the Workbench project page and ANSYS ACT for ANSYS Mechanical. 

Alternatives: perl, Lua, linux shell scripts.

vtk VTK
Visualization Library

Did you ever wish there was a toolkit out there that you could use to quickly build a visualization tool?  I know I spent days of my early career writing simple tools from scratch, and spending most of my time on graphics stuff.  Well, VTK is that toolkit.  It consists of C++ class libraries, and includes interpreters for Tcl/Tk, Java, and python.  With python, you can create little applications very quickly without having to know a full object oriented programming language.  The resulting graphics are fast and attractive. If you are going to be writting your own vertical application that works with your FEA or CFD tool, use VTK for the graphics.

paraview ParaView
Visualization Tool 

The first time you use ParaView, your response will most likely be OMG. It is a visualization tool written in VTK.  It reads most FEA and CFD formats, along with pretty much any faceted geometry data format.  [Unfortunately it is not reading the current ANSYS ds.dat file that ANSYS mechanical writes (or a cdb file)  I’ll try and submit a bug report. ]  But it does read a CGNS file, which you can export to from Workbench. 

But we don’t use it for working with ANSYS files so much, we have tools for that. We use it to deal with other file formats like STL, NASTRAN, CGNS, ExodusII, etc…  Very handy and intuitive to use. It is also an example of how powerful VTK is.

Alternatives: OpenCascade

notepad  Notepad++
Source Code Editor 

This is a great text editor.  Newer than most, it builds on the dozens of previous text editors out there.  It does syntax highlighting and auto completion for many languages. For ANSYS users, it has a powerful column editing mode, very sophisticated search and replace, and macro recording and playback.  I’m not aware of an APDL syntax highlighter, but you have PeDAL for that. There are a lot of text editors out there, and this one has bubbled to the top as the most popular at PADT.

Alternatives: Notepad, PSPad, TextPad, UltraEdit, and dozens more

vim Vim/GVim
VI Text Editor 

Some people love VI, the old Unix text editor.  I’m one of those people. I’ve been using VI for over 30 years.  So I have to have a VI editor on my machine and I use it instead of Notepad++ or other text editors. Because I don’t want to touch a mouse, I want to [Esc] jjjj llll .  instead.  Vim is really the only good VI tool out there anymore, and it comes standard on most Linux installs instead of the old Vi.  The windows version works great.

Alternatives: Elvis, Vile, Lemmy

openoffice OpenOffice
Word Processor, Spreadsheet, Slide Shows, Database 

Let’s be honest, MS Office dominates this type of tool. It works, everyone has it, and everyone knows it.  But sometime you don’t want to fork over cash to those guys in Seattle. Or maybe you spend your day on Linux.  OpenOffice is about 90% of what MS Office does, and it is free. It kind of died at Sun when they got bought by Oracle.. Since Apache has taken up the market, it has seen a lot of enhancements.

Many people just think about the word processor, but remember it has a simple drawing tool, an equation editor, a a very good database program.

Alternatives: GoogleDocs, LibreOffice

latex LaTeX
Document Perpetration System 

How do you tell an engineer with an advanced degree from one who just has a BS?  The one with the MS or PhD like LaTeX.

Traditionally the tool of thesis writers, LaTeX has significant utility for the ANSYS user.  It allows you to create nice looking documents by imbedding tags in the document.  A pain when we have WYSIWYG editors, but very useful if you want to use scripting to create a document.  It is also a great way to create very good looking equations and tables.  Think of it as HTML for nice looking documents.

Alternatives: Word Processors

cutepdf CutePDF
PDF Creator/Writer 

This tool is not as important as it once was, since many programs write to PDF for you. But every once in a while you run across one that does not.  It installs like a printer, so anything program with a print command allows you to save as PDF. 

Alternatives: Adobe Online PDF Creator, PDF reDirect, PDFCreator, and a ton more.

adobe-reader-logo Adobe Reader
PDF Viewer 

I almost left this off the list, but to be fair I included this. If you don’t have Acrobat Reader, you must live in a cave.  It is pretty much required to do business in this day and age.



PostScript Tools 

Ghostscript is an old Gnu project that contains tools for working with PostScript.  Ghostview is the viewing tool on Linux, although it has been replaced by GV.  GSView is a viewer for Windows.  Look at the website to learn about which tool you should be using.

If you just look at PDF’s, then Adobe Reader is all you need. But if you have an older program that output PostScript directly, or you want to write a tool that create PostScript, then this toolset is for you.


Windows Snipping Tool
Screen Capture Tool 

This comes with all modern Window’s operating systems.  And, to be honest, this is the one free utility most of us use more than any other.  Who saves images to files any more, we just snip them!  If you don’t have it in your task bar, put it there and get used to using it. 

Your Linux Desktop Environment will have a similar tool: KSnapshot or GNOME Screenshot


Screen Capture Tool 

CamStudio is an open source tool for capturing video and audio off your screen.  Now one may want this to create screen grabs of “Lost in Space” reruns… but what does an ANSYS user need this for.  We use it to make tutorials for other users.  It is a great way to capture what you are doing on your screen for training or to share with co-workers.

Alternatives:  We mostly use commercial tools for this… see the next article.


Image Editing Tools 

I hate the name of this product. The politically-correct-Berkley-grad in me finds it very distasteful. But it stands for Gnu Image Manipulation Program.  It is not Adobe PhotoShop, but every release it gets closer. And in some areas it is better. It runs on Linux and Windows, always a plus.  We use it on our Unix machines to crop and clean up images. It can also be used to combine a series of images into an Animated GIF.  It is not bad at deleting backgrounds to make images with transparency for presentations as well.  It also has a fairly good vector creation layer.

We used to recommend a mixture of free tools to deal with image manipulation and editing, but now we feel that GIMP does it all.

Alternatives; ImageMagick, MS Paint

Movie to GIF MovieToAniGif
Make Animated GIF’s from AVI’s

Everyone uses Microsoft PowerPoint to do presentations, and for most things it works great. But one thing is really sucks at is animations: you have to keep the movie files you are showing in the same directory because you can not embed them.  The simplest solution to this problem is to convert your animations into animated GIF files. Then insert those in your presentation. It also solves the problem of putting animations on your website without using YouTube or Flash.

The tool we use mostly is Move to Animated GIF Converter.  It is old, the last version came out in 2010, but it still works just fine.  Not much to it, point it at an AVI file and then save it as an animated GIF.

Alternatives: There are a bunch of tools out there, we have not used any so can’t really recommend an alternative.

engauge-digitizer Engauge
Converts Images of Graphs into Data

Have you ever asked someone for material properties and you get a scan of a phototcopy of a book page back?  It happens less these days than it used to but you still sometimes get an image of a graph rather than a spreadsheet file.  Have no fear, Engauge is here!  It takes your image and allows you to identify the axis and the scale, then the data.  With a few clicks you have a table of useful data. 

Alternatives: A ruler.

Gnuplot Gnuplot
Plotting Tool

Most FEA tools have their own 2D and 3D Graphing options, and of course Excel does a pretty good job. But sometimes you need more, or you want a plotting tool you can script. Gnuplot is that tool. It has been around forever and has about every type of graph imaginable. As a command line based program with its own scripting language, it can be generated by your programs to get the exact plot that you want.

Alternatives: Python’s matplotlib or PyQtGraph, Scilab

scilab Scilab
Numerical Computation Tool

We don’t us a lot of Matlab here at PADT, we try and beat it out of new grads when we hire them… no not really.  It is a tool that our younger engineers are used to using.  The problem is it is kind of expensive when you use it every once in a while. Scilab is a nice open source alternative.  It works well and runs on Linux and Windows. 

Alternatives: Julia, Sage.


Windows Remote Desktop
Remote Desktop Tool
Built in to Windows Operating Systems

This is another “free” utility that comes with the windows operating system. Strictly speaking, it is not free because you paid for Windows, but it is so important, I thought it it was worth mentioning. 

Accessing your a windows computer remotely was something we can now do all the time, even from a mobile device. And internet connections are fast enough to where you can do real work from a coffee shop, home, or even from an airplane with WiFi. 

More importantly, in March of 2014, Microsoft released apps for iOS, Android, and Mac that work really, really well. We had been using 3rd party apps that were OK, but the new MS apps are great and I log on to my desktop all the time from my iPad and work fairly productively.


Remote Desktop Tool

Remote Desktop works great for Windows boxes.  But if you want to do a remote desktop thing with Linux, or cross platform, we recommend VNC.  There are a ton of VNC tools out there, we seem to use tightVNC, and realVNC.  You need a server on the remote machine, and a viewer on the machine you are using. The viewers are free, not all servers are free.  There are also apps for iOS and Android for VNC viewers.

We recommend using VNC only if you are connecting to a Linux machine from a Windows machine and you don’t want to mess with an X11 server on your Windows Machine (See below for X11 servers for Windows).  VNC does a pixel copy across the network, which is not as fast as X11 or Remote Desktop that send primitives back and forth.

We have not had time to investigate VNC tools like TurboVNC that use VirtualGL and other tools to speed up the sending of the graphics window back and forth. NX (see below) uses VirtualGL

Alternatives: Tons, just google.


Remote X11 Desktop Client and Server

Above we talk about Remote Desktop and VNC as ways to see remote machines.  If you want to see a Linux machine the best free way we have found is to use NX. This is one of those open source tools that is free and not free, and can get confusing.  It works like VNC in that you need a server on your remote machine, and a client on your machine. The client from is free.  The server is something you need to load on the remote machine, and probably comes in your Linux distribution. FreeNX seems to be the most popular.

You should get very nice performance for 3D graphics on your internal internet, and not bad over the internet either.  We recomend NX over Cygwin if you don’t need a full unix clone on your windows machine, if you are just logging in to a LInux box, use NX.

(and yes, we hate that the name is the same as the CAD/PLM tool… causes great confusion)

Alternatives: Cygwin, VNC

cygwin cygwin
Linux on Windows

If you need more than visualization on a remote Linux machine from your Windows box, you actually want to run Linux on top of Windows without rebooting or using a virtual machine, then you need cygwin.  It is a fairly full linux distribution that runs on Windows, including full X11 capability.  We don’t recommend it for people who are not Linux savvy, but if you are and you want to work in that environment, then it works very well.

putty putty
ssh Tool

The best, and most secure, way to connect to a Linux machine is through SSH. If you have NX or cygwin you just open up a terminal and connect. But what if you just want a text connection. Putty is a simple tool that will store your connections and let you log right in and provide you with that terminal.  Better yet, it has an SCP tool (ssh copy) that is very handy for transferring files between machines.

dropbox dropbox
File sharing Tool

There are a ton of “cloud” tools out there that let you load a file up on a server in the sky, backing it up or sharing it with others.  We use Dropbox at PADT for a couple of reasons.  The first is that it is more than a cloud solution, the files you put on Dropbox get copied to all of the computers you have that are connected to your Dropbox.  I keep all the essential files I need every day, and for whatever project I’m working on in a Dropbox folder and I have access to it at home, on my laptop, even on my iPad. 

I also use it to transfer files to other people who don’t know what FTP is.

Alternatives: Box, Copy, GoogleDrive (with Sync)

filezilla filezilla
FTP Tool

Real simulation users FTP from the command line… and waste time doing so.  FileZilla is a great tool that uses a GUI to connect to FTP servers and transfer files by dragging and dropping.  It makes finding files, transferring multiple files, and monitoring those big transfers a breeze.

Alternatives: ftp command line, cURL,lftp

7zip 7-Zip
File Compression Tool

This is the most capable windows based compression tool we have found.  For many people the built in compression in Windows is fine, but if you want other options, and the ability to work with formats besides .ZIP ( including TAR, GZIP, RAR, LZH) this is the preferred tool.

Alternatives: windows compression, we have not used any other free tools for this


I was going to recommend two tools for encryption: TrueCrypt and PGP.  But it looks like both tools are in flux right now. 

TrueCrypt makes virtual drives as files. When you decrypt them they show up as a drive on your machine. Very handy for achieving any special security concerns you may have.  But in march it was mysteriously shut down. They recommend that you use BitLocker which comes free with Windows.  We have not tried it so we can’t recommend it. Too bad, it was a great tool.  An alternative is PGPDisk, but that costs money or you have to compile it yourself.

PGP encrypts files and had great email plug-ins. It was a nice tools for sending customer data back and forth in a secure way.  It was purchased by a series of companies and ended up sort of becoming static. You can read about it on Wikipedia. The good news is that there is an open source version called PGP, available on  You want the GnuPG version which is free.  There are links here to PGPDisk source code as well.

Bottom line, if you need to encrypt, you might as well pay for a commercial version that is supported.

So, that is all of the tools we could think of, a very diverse list.  Remember, put any other suggestions you have in the comments below.

IGES Can’t Stand IGES Anymore!


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.


What geometry format are you using?




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.


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

In the Heart of Oil and Gas Simulation: PADT at ANSYS Convergence 2014 Houston

This years ANSYS user group meeting is off to a great start. I need to change gears from electrical stuff that dominated in Santa Clara last week to oil and gas. Some great applications of simulation to really difficult problems.


ANSYS Acquires SpaceClaim

Big news this morning in the ANSYS world: ANSYS, Inc. has acquired SpaceClaim, makers of a very powerful 3D Solid Modeling tool that has been an add-on for ANSYS products for some time.

Here is the official press release:

Here at PADT we have been long time users of the SpaceClaim products, and big fans. This will certainly secure the focus of the SpaceClaim development team on continuing their work on providing simulation users with the tools they need to create, modify, and add intelligence to their geometry.  The debate of DesignModeler vs. SpaceClaim seems to be settled!

This is a great technology fit, and there seem to be some nice business advantages as well.

Still Time to Attend an ANSYS User Group Conference

conference-2014-logoApril is almost over, and you know what that means? It’s time for the ANSYS Convergence Regional Conference to begin.  These free events are held once a year and are an opportunity for the entire spectrum of ANSYS users to get together for one day. Each event is a bit different, but the goal is the same:  Users share presentations on what they have done and the experts from ANSYS, Inc. share what is new and exciting with the products.  

These events are technical in nature, with a general session followed by specific technical tracks.  

conf2And PADT will be at the Santa Clara and Houston events this year, highlighting our services and products and presenting in Santa Clara.

The four US events are:

There are also 12 events in Asia, 12 in Europe, 7 in Latin America, and 7 in  the Africa/Middle East region.
See the full list here.

Remember, it’s free and always educational.  Even in our modern world of blogs, forums, and webinars, it is valuable to just spend some time talking with experts and other users.

PADT is a “Silver Sponsor” so we would love to see you there!