# MCAD Modeling Methods-Engineering Caculators Have All the Answers

1 Feb, 2006 By: IDSA ,Mike Hudspeth### Software also documents design data.

If You're Like me, you can handle basic math, but need a little help when calculating something really complicated. That's where engineering calculators come in handy.

What does engineering calculation software do? It comes up with the answers. More importantly, it documents everything, not just the answer. How many times have you messed up a calculation on paper by misplacing a decimal or an entire step? My math teachers drilled it into me over the years to write out the process of solving the problem. They call that traceability. Engineering calculation software keeps meticulous track of what is going on. This record can prove valuable both in identifying the cause of errors and in capturing the knowledge that goes into producing a design.

Many engineers use spreadsheets for calculations, but spreadsheets have limitations. For the most part, they don't show intermediate steps. The calculations occur behind the scenes where no one can check them. Consequently, any errors in how a spreadsheet is set up can go uncorrected, sometimes making it into the design. Engineering calculation software makes things a little more visible. Most engineering software charts the equations as they are made so every step is apparent. If there's a mistake, users can go through the math line by line to see where the mistake is.

You heard me right. Unless you installed a corrupt copy of your engineering calculation software, any mistake is a result of human error. What was it HAL said in 2001? "These things are always due to human error."

**What's Out There?**

**Mathcad** ($1,195) from Mathsoft is one example of the commercial software available (figure 1). Interestingly, it uses a spreadsheet-like capability, updating the entire equation when any values are changed. This makes it easy to examine the impact that even simple changes have. Another advantage is that users can save out templates and documents for reuse later by others. Mathcad even allows users to attach nonequation data, such as detail notes that explain where values originated and why they were used. These notes can benefit both current workmates and future designers who pick up the data ten years down the road.

Figure 1. When step-by-step explanations are necessary, Mathcad lets users attach metadata—text and other documentation that isn t part of the equation. |

Look for software that has some kind of auto-saving feature. It's my general rule of thumb that I save after doing anything I don't want to do over again. (I actually pressed save while I wrote that.) Setting software to save work at regular intervals will safeguard against forgetfulness. Mercifully, Mathcad just added this function to its latest release.

**Mathematica** ($1,549.99) by Wolfram Research (figure 2) is capable of a wide range of tasks, including complex calculations that involve thousands, even millions of terms; visualization; differential equations; numerical modeling; simulation and more. Though Wolfram says the program can be used by elementary students, I've heard from other users who find the interface challenging. Unless you're already a programmer, Mathematica is going to take a while to figure out. Have patience. There are several interface choices, such as an Internet browser.

Figure 2. For all us technology geeks out there, Mathematica is a 64-bit program that supports multicore processors. Taking advantage of workstation muscle can solve big math problems quickly. |

**Maple** ($1,995) from Maplesoft is another popular choice. One interesting feature in Maple is handwriting recognition. With well over one thousand different symbols available, it can quickly become difficult to find the one you want to use. Not a problem with Maple—just open the Symbol Recognition tab, draw the symbol needed and hit the search button. Maple provides a list of symbols it thinks might match (figure 3).

Figure 3. Users looking for a particular symbol just need to draw it in Maple, and the software brings up a database of matches. |

**You Get What You Pay For?**

When looking at engineering calculation software, you might realize you need the program just to add up its costs. It can be as expensive as 3D modeling software. All is not lost. There are resources available on the Internet, some of which are free. Some ask that you become a member of whatever group is sponsoring the Web site; others let you crunch your numbers for free. The downside of most free software is that it's generally old. Regardless, you can find programs to do just about anything you need to do, although support may be an issue.

**Document your Calculations**

Choose carefully when looking for an engineering calculation application. All programs are not equal, or up to the task at hand. Users can download evaluation copies of most software to try it out before buying. This will save a lot of time, money and aggravation. Look closely at the software's interface. Does it make sense? Does it fit into your current workflows?

Engineering calculation software gives designers confidence in what they design by documenting design calculations every step of the way. It can be costly, but so too are errors.

*Mike Hudspeth, IDSA, is an industrial designer, artist and author based in St. Louis, Missouri.*