The real payoff of 3D Printing: Free Donuts

I've got a new side project - one that's not really in full motion yet - in fact it is hardly started - but it still needed a mascot, an icon, a persona. Isn't that the most fun part of any project, naming it and giving it personality? Yes, of course it is.

Well, for this one, we decided the personality would be a Donut - yes, with a capital D. And please accept this simpler spelling rather than the annoying and all-too-accurate Doughnut spelling.

As with any good product, it's a loser without a 3D Printed product logo - so - the quest to 3D Model and 3D Print a frosted, sprinkled, delicious Donut began.

Design Goals

What I wanted most out of this model was for the final product to actually look like a donut - unmistakably. 

For man made objects which have structure - like buildings or cars or, uh, Raspberry Pi cases, it is pretty easy to represent the object in 3D modeling. 

But for things which occur naturally in our environment - like a Donut - it's a bit harder. I wanted to capture the Donut in it's natural state - soft, sugary, harmful, yet delicious. 

Are you hungry yet?

The type of Donut I selected to model was also critical. I choose a broadly accepted favorite - the Chocolate Frosted Sprinkled Donut - knowing that done right, it would be impossible to deny.

Design Start

Let's face it - without the frosting, the Donut project would be a simple Torus - the rounded and circular shape often called a... Donut. The hard part was the frosting. I literally stared at a picture of donut for 7 hours straight (well... maybe it was 7 minutes, but you get the idea) before figuring out a strategy to achieve frosting which had both a rounded top to match the contour of the Donut and drippy sides to represent that perfectly desirable, about-to-melt look. 

First, I drew a splatter shape with the Spline tool (just random curves connected at the end into a circle. Then I drew another similar shape - smaller and inside the first - for the inside part that would fit against the Donut hole. I extruded the space between the two shapes into a donut-like splatter shape - 4mm high.

The main issue now was to give it a curve to match and sit atop the donut.

Now, I duplicated the donut and sat the splatter shape on top of it - sinking it almost all the way down into the top of the donut. I then sized the splatter so that the ends barely touched the outer part of the donut.

Donut Design Magic

The magic was about to happen. 

I used the "Combine" / "Intersect" tool - with a copy of the Donut as the source - and the splatter as the target - to get a perfectly contoured splatter shape which could be fit on top of the donut! I simply enlarged it slightly and raised it to sit on top of the Donut.

The sprinkles were easy-ish - they are each just small cylinders (approx 2-3mm long and 1mm diameter) with rounded ends. I placed each individually atop, and slightly sunken into, the chocolate frosting.  I also gave each a slightly random tilt and turn - giving that "dropped onto the frosting in a carefree manner" look. (I've lost you, haven't I)

Additional Details

To make the Donut lay better on the printer bed, I added a 3mm wide flat cylinder to the bottom aligned perfectly to the tangent points that were touching the bed. Of course, I also added a key ring loop so the Donut could be conveniently displayed to make all around you jealous.

Some resizing steps were taken - harder that I had hoped - to make the Donut small enough to print fast, but big enough to notice the detail. And - as I have done before - I used Sharpies (tm) to color the donut quickly.

The model

The MkrClub Delicious Donut model can be found here - where it will attract the most hungry, sweet-toothed 3D Print enthusiasts.