# Things We Love About PTC Mathcad: Engineering Notebooks and Space Travel

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Engineering notebooks haven’t always been digital. Some of history’s famous inventors stored their life’s work in regular notebooks - Thomas Edison had over 2500! And while the simplicity and nostalgia of graph paper is understandable, digital engineering notebooks are smarter, more versatile, and outrun your old school notebooks in a number of ways. Today we’ll tackle two of them: project documentation and unit sensitivity.

It’s Around Here Somewhere . . .

How many times have you been asked a question about a design and spent time paging through old files? Ever spend a lunch break following a month-long email thread hoping you found every piece of a puzzle? Now think of what happens when an engineer leaves the company. Do you have easy access to their knowledge by looking through loose notebooks left on their desk? Can you reconstruct their logic by examining their designs?

The core problem is your decision history isn’t in one place. The documentation and designs are disconnected. It’s tough to give answers with confidence if you don’t know that you have all the facts.

PTC Mathcad, paired with Creo, erases that uncertainty. PTC Mathcad can imbed documentation worksheets directly into the CAD model. Data is passed between the applications, updating or validating the model and notations as needed. So not only are you saving the entire history of the notations and decisions made during the design and validation phases, but you’re also making it available to other engineers and stakeholders who need it.

Want to see a simple demonstration? Check out the video.

Engineering Unit Conversion
and Rocket Ships

Unit sensitivity is one of the many ways Creo and PTC Mathcad understand each other. For example, if you’re building a spacecraft destined for Mars, accurate calculations are paramount. When you write a unit as centimeters in your notebook and the model is left as inches, the spacecraft may not perform as expected. If your notes are separated from the design, it’s even harder for anyone in the team to catch the error. The end result could be expensive and embarrassing.

Let’s take a hypothetical example. Your spacecraft has a part shaped like a cylinder. To start, we model it in Creo and assign some approximate numbers. It’s diameter for now is 4 and its height is 10, using inches as its unit. We’ll rely on PTC Mathcad calculations to drive the actual dimensions we need for the part.

The PTC Mathcad worksheet calculation tells us the diameter of the cylinder is actually 0.08 meters (8 centimeters). Because PTC Mathcad is unit sensitive, it doesn’t just pass the number 0.08 to Creo. It passes both the number and the unit. The model knows the 0.08 isn’t inches, it’s meters. As long as unit sensitivity is turned on in the relations table, the model’s diameter will instantly resize to 3.15 inches, matching the results of the worksheet.

Bridging The Gaps

Connected documentation and unit sensitivity are core features of PTC Mathcad and its integration with Creo. We’re not telling you throw away your pencils and scratch paper just yet. We do encourage you to blend the old ways with the new, using what both history teaches and technology enhances. Imagine what Edison could have accomplished if his notebooks were digital, searchable, and always connected.

P.S. Did you know PTC Mathcad can pass units to third party tools, too? If you’re new to PTC Mathcad and want to check out some of these smart features for yourself, download your free-for-life copy of PTC Mathcad Express and find out why it’s the most powerful and adaptable engineering notebook.