A friend was missing knobs for some audio mixing equipment, so one of our members re-created a 3D Model using one of the remaining knobs. (Now a spare can be 3D Printed in less than an hour!)

Click the video below to see the sequence of building the 3D CAD model, using Autodesk Fusion360.

To re-create an existing object we use digital calipers to precisely

measure the components that make up the knob.

We measure each part of the object, including every minor detail – like the tiny (1mm) notches on the inside!

Then we build 3D objects in our CAD software, one component at a time.

Some objects will become part of the final knob – like this Cylinder, which was then modified with  to fit the main shape:

A cylinder is an extruded circle.

“Chamfer” cuts at an angle[/caption]

“Fillet” cuts along a radius, creating rounded edges.



Chamfered cuboid

Combined objects

After the “join” operation is performed, they become a single, solid object.

Some objects will be used as tools – to “cut” (or subtract) material away from the main parts – like the cylinders and cuboids (extruded rectangles) that make up this very unique “cutting tool”:


Cuboids (extruded rectangles)

Modified cylinder

Complete “cut” tool

The combination of all these objects, when subtracted from the original model, will leave empty space in the exact shape of the “tool” objects we’ve used to cut it.

Main body of the knob, before “cut” (subtract)

Knob body after the “tool” objects were cut/removed.

Once the 3D model is complete, we can use Computer-aided Machining (CAM) to create instructions for machines used in many different manufacturing techniques:

  • Additive Manufacturing (3D Printing, layered modeling)
  • Subtractive Manufacturing (CNC Milling, Laser-Cutting, CNC Plasma, CNC Waterjet)
  • Mold-making (Injection-molding, Vacuum-forming, Spin-forming)

The true beauty of 3D modeling in digital form is being able to modify the measurements of nearly *any* component of our model in seconds, without having to re-do all of our work!

We can also make constant modifications (or our friends across the ocean can!) Each iteration of the 3D model can be machined, and tested, without having to re-invest all of our design labor each time.

3D Printing makes the iterative process more rapid – because we can easily and quickly create physical objects from our models at a very low cost! (In some cases, plastic from the non-working prototypes can even be recycled into a future iteration!)

Not only can our musician friend fine-tune his mixer with matching knobs, he’s even thinking of customizing his equipment with his favorite colors… who knows – maybe we’ll even go vintage and make some out of real wood!

With 3D Modeling – there truly is no limit to your creativity!