## 3D Color Printing the 2014 Arizona SciTech Festival Awards

The best way to promote and celebrate science and technology is with science and technology.  And this year PADT was able to do just that by using 3D Color Printing to make the recognition awards for the 2014 sponsors of the Arizona SciTech Festival.

The Arizona SciTech Festival is a new but growing player in the Arizona STEM landscape.  After three short years it has become the preferred way for science and technology companies and educators to engage with the public.  This year’s festival, held in February and March, was a huge success.  And none of it would be possible without the support of sponsors. PADT was honored to once again the awards that are given to these sponsors in recognition of their contributions.

In the past we mixed traditional manufacturing and 3D Printing to make the awards. But this year we were able to use our new Stratasys Objet500 Connex3 to make the bulk of this years awards, and our Stratasys FORTUS 400 to make the stands.  The resulting awards are better than we had hoped for.

### The Process

The way the color printer works is you have to create a separate STL file for each color you want to print. So I needed to take a 2D vector art file and convert it into a collection of 3D STL files that represent the part I want printed.

I started by taking an Adobe Illustrator file of the AZ SciTech Festival logo, cleaning it up, and exporting it as a *.DWG file.

I then imported it into my CAD tool. I happen to use SolidEdge, but the process should work with any modern CAD tool. I had to clean up the lines a lot.  In a graphic art image you can have small gaps, little line segments, and even polygons that self intersect. But in CAD you have to clean that all up. Plus some features were just too small to see in the 3D Printed object, so I simplified those. This was the most difficult part of the process.

Once everything is clean you simply go through and extrude each polygon that you want printed, using the cleaned up sketch as your geometry.  Here is the first solid, and the simplest, the tail:

Once all the polygons are extruded, I assigned colors so I could visualize what the final part would look like. I also put a round on all the top edges, knowing from experience that even putting a small round on a part like this will increase the final parts attractiveness.

The base needed to be a separate solid, because I needed it to be a different color. So I just made a new part for that and made an assembly. This keeps all of the solids separate. The letters were made just like the lizard logo, I went in to Adobe Illustrator and created the text outline, following the circle that defines the award. I exported that as DWG, imported it into SolidEdge, then extruded each letter.

The next step was to export the assembly as an STL file.  This file contained all the solids.  This was read in to the software that comes with the Objet500 Connex3. The operator then had to click on each object and assign a color from the chosen pallet.  It turns out that the official ScitTech Festival colors match one of the pallets closely, so we were able to get all the colors in the print.

Once this was done, we simply printed 28 at a 3″ diameter, and 9 at 2″. Here is a video showing the printing process.

The resolution and brightness of the colors was very nice. Here are some images. Color parts just look better.

For the base, I just came up with something that was thin and easy to build in using FDM because I wanted a strong part that was inexpensive that would also take a decal with the recipients name on the front, and information about the award on the back.

Here is a stack of the printed bases.

### Why Does it Matter

This effort is great example of the power of 3D Printing to a create a smaller number of custom objects. Standard awards form an awards shop are cheaper, but they are generic.  Using traditional methods to make custom awards is expensive and often labor intensive.  By making the whole award using a 3D Printer we were able to reduce the cost and the time for these unique objects, and were able to use advanced technology to highlight the sponsorship of an event that celebrates just that.  Kind of cool.

It is also a great example of the long term power of 3D Printing.  As was covered in a recent blog post, the real power of this technology is that it lets people without manufacturing or craftsman skills to create real objects, without a collection of equipment they don’t need or don’t know how to use. The applications of this power are endless.

## 3D Thursday – 4th of July Style

I was in search of something Independence Day/3D printing related to celebrate the 4th of July.  It seems like a lot of people had the same idea.  Thomas Jefferson……yup, he was 3D printed at RedEye on Demand.  President Obama was 3D printed at the first ever White House Maker Faire last month.   So, after sifting through replicas of the Statue of Liberty or American Flags, I came across something really cool.

His design is in 4 separate sections that can be taken apart to see the beautiful and intricate detail on each of the floors.  It’s a beautiful design of a very important part of American history.

And just for fun, here is an interesting article about the creation of an exact replica of the Liberty Bell using 3D scanning.

Happy 4th of July!

## A look inside the Objet500 Connex3 Multi-material 3D printer

This week our we printed some beautiful multi-colored sponsor awards for the 2014 Arizona SciTech Festival which officially launches in August.  Intern extraordinaire, Diserae Saunders, placed a GoPro inside our Objet500 Connex3 to record the magic.  Enjoy the video and check out the Arizona SciTech Festival for information on this great program that promotes science, technology and innovation in Arizona!

We love to see our customers succeed – everyone here that has worked with Ulthera knew it would only be a matter of time before a large player recognized the value of this company. And, we just learned today that the German pharmaceutical company Merz is buying Ulthera for $600,000,000. Here is a link to an article on the sale, and here is a link to the press release PADT worked with Ulthera to help them redesign their hand-piece design. The process, called Ultherapy, is a non-surgical, non-invasive procedure for the face that uses high density, focused, ultrasound and the body’s own natural healing process to lift, tone, and tighten loose skin. Some of our employees also volunteered to test the device and pose for marketing material. Read about the work we did in a case study we published a while back. Congratulations to everyone at Ulthera and we can’t wait to work with them again to help improve and grow this device and others in the future. Posted in News, PADT Medical | | Leave a comment ## Recommended Free Utilities for the ANSYS User’s Toolbox What 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:  pythonScripting Languagewww.python.org 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.  VTKVisualization Librarywww.vtk.org 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.  ParaViewVisualization Toolwww.paraview.org 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++Source Code Editornotepad-plus-plus.org 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/GVimVI Text Editorwww.vim.org 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  OpenOfficeWord Processor, Spreadsheet, Slide Shows, Databasewww.openoffice.org 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  LaTeXDocument Perpetration Systemwww.latex-project.org 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  CutePDFPDF Creator/Writerwww.cutepdf.com 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 ReaderPDF Viewerget.adobe.com/reader 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.  GhostscriptGhostviewGSViewPostScript Toolspages.cs.wissc.edu/~ghost 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 ToolScreen Capture Toolen.wikipedia.org/wiki/Snipping_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  CamStudioScreen Capture Toolcamstudio.org 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.  GIMPImage Editing Toolswww.gimp.org 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 MovieToAniGifMake Animated GIF’s from AVI’swww.evanolds.com/movtogifsimple.html 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.  EngaugeConverts Images of Graphs into Datadigitizer.sourceforge.net 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 GnuplotPlotting Toolwww.gnuplot.info 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  ScilabNumerical Computation Toolwww.scilab.org 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 DesktopRemote Desktop ToolBuilt 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.  VNCRemote Desktop Toolwww.tightvnc.comwww.realvnc.com 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 VirtualGLAlternatives: Tons, just google.  NX NXRemote X11 Desktop Client and Serverwww.nomachine.com 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 www.nomachine.com 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  cygwinLinux on Windowswww.cygwin.com 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.  puttyssh Toolwww.putty.org 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.  dropboxFile sharing Toolwww.dropbox.com 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)  filezillaFTP Toolwww.filezilla-project.org 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  7-ZipFile Compression Toolwww.7-zip.org 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  Encryption 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 www.pgpi.org. 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. Posted in The Focus | Tagged , , , | 2 Comments ## 3D Scanning and 3D Printing for Makers Off to a great start sharing the Capture Scanner and Geomagic Software at TechShop in Chandler. Great group, great questions. Posted in News, The RP Resource | Tagged , , | Leave a comment ## PADT Medical Team at AZBIO Expo 2014 Representatives of the PADT Medical team are having a great day at this years AZBIO Expo in Scottsdale. We brought along some of the medical device projects we have worked on and have been chatting with past, current, and future customers. Margaret and our “assistant” posed for this picture of the booth: Insert skeleton jokes here. The event is a fantastic reminder of how vibrant the local Bioscience community is in Arizona. From genetics to algae, pharma to med devices, the state has key players in almost every industry. And every year our three state universities make stronger and stronger contributions to basic research in this area. There is a lot going on and this event is one of the best places to catch up on the wide ranging impact Arizona Bioscience companies are making. Posted in News, PADT Medical | Leave a comment ## An inside look at our Connex500 We wanted to see what 3d printing looked like from the inside of the machine so our new intern, Diserae Sanders, placed a GoPro inside our Connex500 during a print job. The item being printed is a demo bicycle pedal printed in multiple materials. This video is the first in a series we plan to do on 3D printing. If there is something you would like to see us do a video on, please post it in the comments below. Posted in Fun, News, The RP Resource | | Leave a comment ## 3D Scanning & Printing for Makers Attention Makers, Tinkerers & 3D Enthusiasts When : Monday, June 23, 2014 6:00 PM to 7:00 PM Where: TechShop Chandler 249 E. Chicago Street Chandler, AZ 85225 Attend Live – Register Now Attend Virtually – Register Now Join us for an evening of 3D Scanning and Printing!!! We will be discussing some practical ways to utilize 3D scanning and printing specifically for Makers. Whether you are new to 3D printing or you need a refresher on how 3D scanning can help with your designs, this workshop is for you. Anyone, novice to seasoned expert, is invited and encouraged to attend and share their knowledge and questions. Two ways to participate: In Person If you are in the area, please join us at Tech Shop Chandler by registering HERE. Virtually If you can’t be here in person, you can join us virtually by registering HERE. Light refreshments will be served (only to in-person attendees, sorry virtual participants) Registration is required as space is limited. If you have any questions, please contact Kathryn Pesta at kathryn.pesta@padtinc.com or 480.813.4884. Posted in Fun, News, The RP Resource | Tagged | Leave a comment ## Stratasys adds flexible color to their digital material palettes Earlier this week, Stratasys announced the addition of 10 new color pallets expanding the digital materials offering to represent hundreds of new options of both flexible color materials and rigid gray materials available for the Objet500 Connex3 Color Multi-material 3D Printer The first three pallets are built using TangoPlus combined with combinations of VeroCyan, VeroMagenta and VeroYellow. These new pallets allow for the printing of a range of colors and translucent tints in nine Shore A values (Shore A 27-95). Three additional pallets using TangoBlack Plus and combinations of VeroCyan, VeroMagenta and VeroYellow allow for users to blend a wide range of subtle vibrant-to-dark shades into the same part with TangoBlack Plus in seven Shore A values. The final four palettes that were introduced offer additional combinations of VeroWhite and VeroBlack with either VeroCyan, VeroMagenta or VeroYellow allowing for users to build sophisticated prototypes in a range of subtle grays alongside muted or vibrant color. The addition of these ten palettes combined with their existing palettes allow for virtually limitless combinations of flexible, rigid and translucent colors in one print job. “The Objet500 Connex3 is the only 3D printer that combines colors with multi-material 3D printing. The ability to mix rigid, flexible, transparent and opaque colors offers users unprecedented versatility to design and perfect products faster,” says Stratasys Director of Materials & Applications Fred Fischer. “By extending the range of material options available, users can improve workflow speeds and enhance efficiency.” These new options are available immediately to Objet500 Connex3 Color Multi-material 3D Printer owners through a free software update. Check out this great video on the new materials. Posted in Fun, News, The RP Resource | | Leave a comment ## Slide Rules, Logarithms, and Compute Servers If any of you have been to PADT’s headquarters in Tempe, Arizona, you probably noticed the giant slide rule in the middle of our building. You can see a portion of it in the picture below, at the top of our Training, Mentoring, and Support group picture. This thing is huge, over 6 feet (2 m) from side to side, in its un-extended position hanging on the wall. In theory a gigantic slide rule could provide more accuracy, but our trophy, a Kueffel & Esser model 68 1929 copyrighted 1947 and 1961, was intended for teaching purposes in classrooms. Most engineers had essentially pocket size or belt holder sized slide rules, also known as slip sticks. For the real thing, here is a picture of a slide rule used by Eric Miller’s father Col. BT Miller while at West Point from 1955 to 1958 as well as during his Master’s program in 1964. Why do we care about the slide rule today? Have you ever seen World War II aircraft, submarines, or aircraft carriers? These were designed using slide rules and/or logarithms. The early space program? Slide rules were used then too. Some phenomenal engineering was accomplished by our predecessors using these devices. Back then the numerical operations were just a tool to utilize their engineering knowledge. Now I think we have a tendency to focus on the numerical due to its ease of use and impressive presentation, while perhaps forgetting or at least de-emphasizing the underlying engineering. That’s not to say that we don’t have great engineers out there; rather it’s a call to energize you all to remember, consider, and utilize your engineering knowledge as you use your simulation tools. By contrast, here is a picture of PADT’s brand new server room, with cluster machines being put together in the big cabinets. Hundreds of cores. What about the giant slide rule? My father found a thick book at an estate sale a few months ago. There are a lot of retirees living in Arizona, so estate sales are quite common and popular. They occur at a life stage when due to death or the need for assisted living, folks are no longer able to live in their home so the contents are sold, clearing out the home and generating some cash for the family. This particular estate sale was for a retired engineer. The book caught my father’s eye, first because it was quite thick and second because the title was, Mechanical Engineers’ Handbook. Figuring it was a bargain for the amazing price of$1.00, he bought it for me.  This book is better known as Marks’ Handbook.  It’s apparently still in publication, at least as late as the 11th Edition in 2006, but the particular edition my father bought for me is the Fifth Edition from 1951.

Although the slide rule is mostly a curiosity to us today, in 1951 it was state of the art for numerical computation.  While Marks’ has a couple of paragraphs on “Computing Machines”, described as “electrically driven mechanical desk calculators such as the Marchant, Monroe, or Friden”, the slide rule was what I will call the calculator of choice by mechanical engineers at the beginning of the 2nd half of the 20th century.

As an aside, these mechanical calculators performed multiplication and division, using what I will describe as incredibly complex mechanisms.  Here is a link to a Wikipedia article on the Marchant Calculator:  http://en.wikipedia.org/wiki/Marchant_Calculator

Marks’ Handbook devotes about 3 pages to the operation of the slide rule, starting with simple multiplication and division and then discussing various methods of utilization and various types of slide rules.  It starts off by stating, “The slide rule is an indispensable aid in all problems in multiplication, division, proportion, squares, square roots, etc., in which a limited degree of accuracy is sufficient.”

The slide rule operates using logarithms.  If you’re not familiar with using logarithms then you are probably younger than me, since I recall learning them in math class in probably junior high in the late 1970’s.  The slide rule uses common logarithms, meaning the log of a number is the exponent needed to raise a base of 10 to get that number.  For example, the common log of 100 is 2.  The common log table in the 1951 edition of Marks shows us that the common log of 4.44 is 0.6474.  For the sake of completeness, the ‘other’ logarithm is the natural log, meaning the base is the irrational number e, approximated as 2.718.

Getting back to common (base of 10) logs, the math magic is that logarithms allow for shortcuts in fairly complex computations.  For example, log (ab) = log a + log b.  That means if we want to multiple two fairly complicated numbers, we can simply look up the common log of each and add them together.  Similarly, log (a/b) = log a – log b.

Here is an example, which I will keep simple.  Let’s say we want to multiple 0.0512 by 0.624.  On a calculator this is simple, but what if you are stranded on a remote island and all you have is a log table?  Knowing the equations above, you can look up the log of 0.0512 which is 0.7093-2 and the log of 0.624 which is 0.7952-1.  We now add:

Writing that sum as a positive decimal minus an integer is important to being able to look up the antilogarithm or number whose log is 0.5045 – 2.

Looking up the number whose log is 0.5045 we get 3.195, using a little bit of linear interpolation.  The “-2” tells us to shift the decimal point to the left twice, meaning our answer is 0.003195.  Thus, using a little addition, some table lookup, a bit of in the head interpolation, and some knowledge on how to shift decimal points, we fairly easily arrive at the product of two three digit fractional numbers.  Now you are free to look for more coconuts on the island.  Or maybe get back to a hatch in the ground where you need to type in the numbers 4, 8, 14, 16, 23, and 42 every 108 minutes.  Oops, I’m really becoming Lost here…

Getting back to the slide rule, one way to think of it is a graphical representation of the log tables.  In its most basic form, the slide rule consists of two logarithmic scales.  By lining up the scales, the log values can be added or subtracted.  For example, if we want to multiply something simple, like 4 x 6, we simply look from left to right on the scale on the ‘fixed’ portion of the slide rule to get to 4, then slide the moving portion of the slide so that its 1 lines up with the 4 found above on the fixed portion.  We then move left to right on the movable scale to find the 6.  Where the 6 on the movable slide lines up with on the fixed portion is our solution, 24.  What we’ve really done is add the log of 4 to the log of 6 and then find the antilog of that result, which is 24.  Now that we’ve found 24, we’re not Lost

We don’t intend to give detailed instructions on all phases of performing calculations using slide rules here, but hopefully you get the basics of how it is done.  There are plenty of online resources as well as slide rule apps that provide all sorts of details.  Besides multiplication and division, slide rules can be used for squares and square roots.  There are (were) specialty slide rules for other purposes.  Note that with additional knowledge and skill in visually interpolating on a log scale, up to 3 or even 4 significant digits can be determined depending on the size of the slide rule.

The author, attempting to prove that 4 x 6 is indeed 24

After having studied the Marks’ section on slide rules, experimenting with a slide rule app on an iPad as well as the PADT behemoth on the wall, I conclude that it was a very elegant method for calculating numbers much more quickly than could be done by traditional pencil and paper.  It’s must faster to add and subtract vs. complicated multiplication and long division.  My high school physics teacher actually spent a day or two teaching us how to use slide rules back in the early 1980’s.  By then they had been made functionally obsolete by scientific calculators, so looking back it was perhaps more about nostalgia than the math needed.  It does help me to appreciate the accomplishments made in science and engineering before the advent of numerical computing.

The preparation of this article has made me wonder what the guys and gals who used these tools proficiently back in the 1930’s, 40’s, and 50’s would think if they had access to the kind of compute power we have available today.  It also makes me wonder what people will think of our current tools 50 or 60 years from now.  When I first started in simulation over 25 years ago, it would have seemed quite a stretch to be able to solve simultaneously on hundreds if not thousands of compute cores as can be done today.  Back then we were happy to get time on the one number cruncher we had that was dedicated to ANSYS simulation.

Incidentally, this article was inspired by my colleague David Mastel’s recent blog entry on numerical simulation and how PADT is helping our customers take compute servers and work stations to the next level:

If you are ever in our PADT headquarters building in Tempe, don’t forget to look for the giant slide rule.  Now you will know its original purpose.

Posted in Fun, The Focus | Tagged , , | 2 Comments

## PADT Customer GlobalStar Featured in News Report

We were pleased to hear from customer GlobalStar that two of the products PADT  worked on for them were featured on a New Orleans television station. The Spot Gen3 and Spot Trace are great devices that communicate to the GlobalStar satellite network no matter where you are, telling people where you are, that your assets have moved, or informing emergency services that you need help.  We learned in the story that SPOT systems had resulted in over 3,000 rescues world wide.  As the Spot Trace usage grows, we hope to see similar statistics for lost and stolen assets recovered.

View the video here:

You can review the work that PADT did on the Spot Gen3 in a case study here.

They haves some great product videos. Here is one for the Spot Trace and another for Spot Gen3.

## 3D Printing brings history to life

Did you hear that they have 3D printed Vincent van Gogh’s ear? How about the 3D printed spine of King Richard III?  This week alone 3D printing has given us two amazing examples of how this technology can be used to look at history in amazing new ways.

In the case of van Gogh, researchers used real living cells from his great-grandson to bioprint the cells to resemble van Gogh’s severed ear.  The ear is being kept technically alive in a nutrient solution and is said to be able to actually “hear”.  You can read more about this amazing application here.

King Richard III has been famously written as having a hunched back by William Shakespeare.  Anthropologists at the University of Cambridge wanted to determine if the description was accurate or exaggerated. Utilizing CT scans to create a model of the spine they were able to create 3D printed replica of his spine based on the models.  It turns out that while he did have terrible scoliosis, there was no evidence that he had a hunch as described by Shakespeare.  You can read more about this research here.

Just two of many new and innovative ways to integrate 3D printing into just about anything!

## 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.

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

Posted in The Focus | Tagged , , , , , , | 1 Comment

## why does no1 respon to my request for help (Some Pointers to Students Looking for Help on Forums, Social Media, and Blogs)

[Note: I know I misspelled respond… that is the point] As many of you know, PADT hosts a very successful mailing list and forum called XANSYS.org. It is one of the most successful online community help places I have ever seen.  There are a lot of reasons for that success, but the biggest is the moderators and how strongly they enforce rules for those posting.  Especially on using complete sentences, punctuation, showing that you have tried, and fully identifying yourself.

I bring this up because I’ve seen several posts on Facebook and LinkedIn groups for ANSYS users that just don’t get many responses, or don’t get the quality of response that posts on XANSYS get. I thought it might not be a bad idea to make some comments on the subject and share this post on some of those other forums.  Although I’ll focus on the ANSYS community, what is said applies to any community that supports engineering and technology tools.

## Show Some Effort

The thing that posters need to remember is that they are often asking industry experts to take time out of their busy day to help them.  Those experts want to see some effort put in to the question.  It is very important that the requester form the question in proper English, or whatever language the forum uses.  Even if the poster is not a native speaker, an effort needs to be made to use full and complete sentences, even if grammar is a bit off. (I won’t comment about speling, because that is a my weakest area… so I’ll forgive others on that one)

The easiest way to show a lack of respect to the people you want to answer your question is to not use capitalization or punctuation. As someone commented one time on XANSYS

“If you can’t find the time to use a shift key, I don’t have the time to answer your question.”

The most famous “bad post” on XANSYS was something along the lines of:

“i have been told to model a turbine blade in ansys, can someone show me how to do this”

Needless to say, no one helped them.  Before you post a question you need to try and figure things out yourself. Read the manual, search the internet, talk to co-workers. Most importantly, just try it.  Trial and error is a great learning experience. If you can’t get that to work or you still can’t find the information you need, then post your question. But, make sure you let people know what you have already done and tried.

The people who can help you on forums want to help, they don’t want to do your homework or your work for you.

The quote above is not just notorious  because it is asking someone to do their work for them, it is also well known because the question is insanely too general.  Questions that are very specific are the ones that are answered the quickest and with the most useful information.  Even if you have lots of questions, break them up – solve one, then try and solve the next.

## Identify Yourself

Saying who you are and where you go to work or school is huge. It is a professional courtesy that says “I have nothing to hide.”  When you hide your identity, people assume you are trying to get someone else to do your work and that you don’t want your professor or boss to know. Or, more seriously, you could be posting from an embargoed country or using illegal copies of the software.

## Give Back

This is obvious.  Many people who answer a lot of questions also ask a lot of questions. Even if you are new to the tool you are asking about, share what you learned on the thread when you get it all working. And as you get better, go back and answer some other people’s questions. Remember, it is a community.

If you want better help from online communities, here are some great links to give you pointers:

The moderators on XANSYS have developed a great set of rules that really work. Follow these and you will do well on almost any site: www.xansys.org/rules.html

A resource that has been around since the dawn of the internet is “How To Ask Questions The Smart Way” by Eric Steven Raymond: www.catb.org/~esr/faqs/smart-questions.html

And the Venerable Guy Kawasaki has a famous post on emails, that has a lot of tips that apply to online posts as well: blog.guykawasaki.com/2006/02/the_effective_e.html

Check out the posts on Xansys.org/forum.html and CFD-Online . They are both vibrant and intelligent communities with good posts.