Other CAD Software Design and Analysis Tools and Concepts
While AutoCAD is truly the market leader for drafting software, it certainly does not operate in a vacuum and is not the only game in town. The list that follows summarizes other major players in the drafting field. The reason you should know about them is because you may run into them in use and may have to exchange files if collaborating. Saying “I’ve never heard of that” is usually not a good way to start a technical conversation in your area of expertise, so take note of the following products.
MicroStation
A major, and really the only serious, competitor to AutoCAD, MicroStation is produced and marketed by Bentley Systems (www.Bentley.com). For historical reasons, the software is widely used in government agencies and the civil engineering community. It comes in full and PowerDraft variations (akin to AutoCAD and LT). The current version is MicroStation V8i. Its file extension is .dgn. Relatively recently, AutoCAD began to open these files via the “import” command. MicroStation, on the other hand, has always been able to open AutoCAD’s .dwg files. Of course, many techniques and even third party software are available to quickly and easily convert one file format to another quickly.
MicroStation is more icon driven but otherwise similar to AutoCAD in many ways. Its 3D capabilities are considered excellent, but its interface can be a bit cumbersome to use by a novice. Its main disadvantage is that it is not an industry standard; it is otherwise excellent software, and its ability to handle xrefs (multiple external file attachments) is unparalleled. Its users sometimes are a fanatical bunch, promoting its virtues against AutoCAD at every opportunity. An objective view of both applications yields an opinion that both have their pros and cons, and those who disparage one over the other usually do not know what they are talking about.
ArchiCAD
ArchiCAD is a popular application among architects, geared toward the Macintosh but also available for Windows. Developed by a Hungarian firm, Graphisoft (www.graphisoft.com), at around the same time as AutoCAD, ArchiCAD took a different approach, allowing for a parametric relationship between objects as well as easier transitions to 3D, as all objects are created inherently with depth. The software has a loyal installed user base of about 100,000 architects worldwide and can interoperate fully with AutoCAD files. The current release is ArchiCAD 16.
TurboCAD
TurboCAD (www.turbocad.com) is a mid-range 2D/3D drafting software, first developed and marketed in South Africa in 1985 and brought to the United States the following year. It was marketed as an entry level basic drafting tool (it once sold for as low as $49), but with constant upgrading and development, TurboCAD has grown over the years to a $1200–$1500 software product for the architectural and mechanical engineering community. It operates on both Windows and Macintosh. The current release is TurboCAD 16, and it also comes in an LTE version similar to AutoCAD LT.
Other Design Software
Some other notable CAD applications include RealCAD, VectorWorks (formerly MiniCAD), IntelliCAD, Form Z, and Rhino, although the last two are often used only for modeling and visualization. This list is not exhaustive by any means, as hundreds of other CAD programs are available.
Many of my students are interested in other aspects of design, and questions often come up as to how AutoCAD fits into the “big picture” of a much larger engineering or design world. To address some of these questions, the following information, culled from a chapter written in 2007 as part of an undergraduate machine design theory workbook, is included. AutoCAD students, especially engineers, may find this informative. The subject matter is extensive and this brief overview only scratches the surface. Ideally, if the reader was not aware of these concepts and the engineering design and analysis software described, this serves as a good introduction and a jumping off point to further inquiry.
CAD (computer-aided design): This is a broad generic term for using a computer to design something. It can also be used in reference to a family of software that allows you to design, engineer, and test a product on the computer prior to manufacturing it. CAD software can be used for primarily 2D drafting (such as with AutoCAD) or full 3D parametric solid modeling. The latter is the software that aerospace, mechanical, automotive, and naval engineers commonly use. Examples include CATIA, NX, Pro-Engineer, IronCAD, and SolidWorks, among others. Included under the broad category of CAD is testing and analysis software.
FEA (finite element analysis): This is used for structural and stress analysis, testing thermal properties, and much more as related to frames, beams, columns, and other structural components. Examples of FEA software include NASTRAN, ALGOR, and ANSYS.
CFD (computational fluid dynamics): This is software used to model fluid flow around and through objects to predict aerodynamic and hydrodynamic performance. Examples of CFD software include Fluent, ANSYS-CFX and Flow 3-D.
CAM (computer-aided manufacturing): The basic idea is this: OK, we designed and optimized our product, now what? How do we get it from the computer to the machine shop to build a prototype? The solution is to use a CAM software package that takes your design (or parts that make up your design) and converts all geometry to information useable by the manufacturing machines, so the drills, lathes, and routing tools can create the part out of a chunk of metal. Examples of dedicated CAM software include Mastercam and FastCAM.
CAE (computer-aided engineering): Strictly defined, CAE is the “use of information technology for supporting engineers in tasks such as analysis, simulation, design, manufacture, planning, diagnosis, and repair.” We use this term to define an ability to do this all from one platform, as explained next.
As you read the CAD and CAM descriptions you may be wondering why CAD companies have not provided a complete solution to design, test, and manufacture a product using one software package. They have, to varying degrees of success. For a number of years, an engineering team designing an aircraft, for example, had to typically create the design (and subsystems) in a 3D program like CATIA, then import the airframe for FEA testing into NASTRAN, followed by airflow testing in CFD software (and a wind tunnel), and finally send each component through CAM software like Mastercam to manufacture it (a greatly simplified version of events, of course).
Obviously, data could be lost or corrupted in the export/import process, and a lot of effort was expended in making sure the design transitioned smoothly from one software application to another. While the final product was technically a result of CAE, software companies had something better in mind: “one-stop shopping.” As a result, CAE today means one source for most design and manufacturing needs. CATIA, for example, has “workbenches” for FEA analysis and CAM. Code generated by CATIA is imported into the CNC machines that (typically after some corrections and editing) produce virtually anything you can design, with some limitations, of course.
As you may imagine, not everything is rosy with this picture. As the specialized companies got better and better at their respective specialties (CAM, FEA, or CFD), it became harder and harder for the CAD companies to catch up and offer equally good solutions embedded in their respective products. Mastercam is still the undisputed leader in CAM worldwide, and NASTRAN is still the king of FEA. CATIA’s version of these has gotten better but is still a notch behind. The situation is the same with Pro/E, NX, and other CAD software.
These high-end 3D packages are also referred to as product lifecycle management (PLM) software, a term you will hear a lot of in the engineering community. As described already, these software tools aim to follow a product from design and conception all the way through testing and manufacturing in one integrated package.
CNC/G-Code (computer numerical code): This is the language (referred to as G-Code), created by the CAM software and read by the CNC machines. G-Code existed for decades. It was originally written by skilled machinists based on the geometry of the component to be manufactured (and sound manufacturing practices). This code can still be written by hand. It is not hard to understand. Most lines start with G, hence its name; and they all describe some function that the CNC machine does as related to the process. After some practice, the lines start to make sense and you can roughly visualize what is being manufactured, just by reading them.
Here are some more specific details on the CAD software mentioned in the preceding section. You may run into many of these throughout your engineering career. It is well worth being familiar with these products. The information is up to date as of press time.
CATIA
Computer Aided Three-dimensional Interactive Application (CATIA) is the world’s leading CAD/CAM/CAE software. Originally developed in France by Dassault for its Mirage fighter jet project (although originally based on Lockheed’s CADAM software), it is now a well-known staple at Boeing and many automotive, aerospace, and naval design companies. It has even been famously adopted by architect Frank Geary for certain projects. CATIA has grown into a full PLM solution and is considered the industry standard, although complex and with a not always user-friendly reputation. The latest version is CATIA V6 R2012.
NX
Another major CAD/CAM/CAE PLM software solution is from a company formerly called UGS (www.ugs.com). This package is a blend of the company’s Unigraphics software and SDRC’s popular I-DEAS software, which UGS purchased and took over. Siemens AG now owns UGS and the NX software. It is used by GM, Rolls Royce, Pratt & Whitney, and many others. The current version is NX 8.5.
Pro/ENGINEER (Creo Elements/Pro)
The third major high-end CAD/CAM/CAE PLM software package, Pro/E (www.ptc.com) is historically significant. It caused a major change in the CAD industry when first released (in 1987) by introducing the concept of parametric modeling. Rather than models being constructed like a mound of clay with pieces added or removed to make changes, the user constructs the model as a list of features, which are stored by the program and can be used to change the model by modifying, reordering, or removing them. CATIA and NX also now work this way. The current version is no longer called Pro/Engineer; the name was changed to Creo Elements/Pro 5.0 in late 2010. The current release is Creo Elements/Pro 2.
Solidworks
SolidWorks (www.solidworks.com) is a mid-range CAD/CAM/CAE software product, first introduced in 1995 by a Massachusetts company of the same name. Dassault, the makers of CATIA, acquired the company in 1997. The SolidWorks installed base is estimated at 1.3 million users, with FY 2009 revenues of over $350 million, making the product a major player in the 3D CAD field. SolidWorks is marketed as a lower-cost competitor to major CAD packages, but the software still has extensive capabilities and caught on quickly in smaller design companies. The current version is SolidWorks 2013 SP0.0.
Inventor
Inventor (www.autodesk.com) is another mid-range product, from the makers of AutoCAD, for solid modeling and design. Considered a low- to mid-range product when first introduced, Inventor matured to become a major competitor to SolidWorks and even Pro/Engineer. The current version is Inventor 2013.
IronCAD
IronCAD (www.ironcad.com) is another vendor in the mid-range market. The software gained ground in recent years due to a user-friendly reputation and a more intuitive approach to 3D design. The current version is IronCAD XG 2013.
Solid Edge
Solid Edge (www.solidedge.com) is also a mid-range product from UGS (now owned by Siemens AG), the same company that makes the high-end NX package. It is comparable to SolidWorks in cost and functionality. The current release is Solid Edge ST5.
Listed next are some of the major software products in FEA and CFD, as mentioned earlier.
NASTRAN
Originally developed for NASA as open source code for the aerospace community to perform structural analysis, NASA structural analysis, or NASTRAN, was acquired by several corporations and marketed in numerous versions. NEiNastran (www.NEiNastran.com) is just one (commonly used) flavor of it. NASTRAN in its pure form is a solver for finite element analysis and cannot create its own models or meshes. Developers, however, have added pre- and postprocessors to allow for this. The current release for NEiNastran is V9, though other companies have different designations for their products.
ANSYS
ANSYS (www.ansys.com) is a major FEA product for structural, thermal, CFD, acoustic, and electromagnetic simulations.
ALGOR
ALGOR (www.algor.com) is another major FEA product for structural, thermal, CFD, acoustic, and electromagnetic simulations.
Fluent
Fluent (www.Fluent.com) is the industry standard for CFD software, holding about 40% of the market. It imports geometry, creates meshes (using GAMBIT software) and boundary conditions, and solves for a variety of fluid flows, using the Navier-Stokes equations as theoretical underpinnings. The company was recently acquired by ANSYS. The current release is Fluent 6.3.