What is Parametric Modelling?

If you’re just starting out in computer-aided mechanical design, I think the first question – what should I use? Often you’ll be bombarded with suggestions of: Solidworks! No, Inventor! Or, Siemens NX!

These software packages all have their strengths and ideal applications, but what do they all have in common? They’re all parametric modellers, now this may be a confusing phrase. All it means is that when you design a part, you start with a blank canvas, then build up a set of shapes and features. These shapes and features are all defined by a set of parameters, and will be applied in a given order. It’s the combination of these features and their order of operation that produces your part!

Now a parametric modeller remembers every step you took to make your part, this means you can go back and change anything you like. In Fusion 360 I can click on any of these feature icons in the design history tab and change their values, amazing! These changes will also update any part drawings I made, this is so much easier than doing it manually.

Design History from Fusion360
The design history of a part in Fusion 360

How not to use a Parametric Modeller

One drawback to this is that the structure of your features is a massive factor in ease of editing once your part is more complex. If you fudge a few features, maybe creating too many new sketches projected from previous geometry, then picking apart each features dependency is going to be a nightmare. Decoupling features from each other as much as possible, and reducing the inter-dependency of geometry will make your workflow much easier. I will be making a post about using master sketches to achieve this.

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