The Cheese Grater In Fusion 360

By now you will all have heard so much about the grille on Apple’s new “Cheese grater” Mac Pro that you might think there was nothing more to say. Before we move on though there’s one final piece of work to bring to your attention, and it comes from [Andy Pugh]. He’s replicated the design in Fusion 360, and used it to produce rather an attractive Raspberry Pi case.

It seems that for Fusion 360 users the problem lies in that package’s method of placing spheres which differs from that of some other CAD software. Using the page linked in our previous coverage of the grille he’s taken its geometry information and produced a video detailing every step in recreating it for Fusion 360. This is where following someone who really knows your CAD package pays dividends, because we suspect it would take us days to figure out some of the tricks he shows us.

The result is the Raspberry Pi case, which is for the Pi 3 and others like it. Sadly we couldn’t break our embargo and tell him about the Pi 4 and its different connector layout, but we’re guessing a halfway competent CAD operator could put together a Pi 4 case. Andy’s files can be found on Thingiverse, so you can all make one for yourselves.

Andy’s appeared here before a few times, not least for his Ner-A-Car motorcycle, and for designing a Robot Wars robot.

34 thoughts on “The Cheese Grater In Fusion 360

  1. Pretty cool. Fusion has issues with patterns, no question. Did any of you also experience the program becoming extremely slow and unresponsive when working with large body patterns? Is there a way around?

      1. It might be the case of weak GPU. Nvidia Quarto is a must for bigger projects. The same goes for RAM and CPU – you need more and better ones. Also gaming GPUs most people have are not very good for CAD, video editing or other profesional uses, for which we have pro GPUs, like Quarto. OTOH pro GPUs suck at gaming…

        1. dont have the same issues with inventor or even solidworks and i rock a regular 1660ti with a ryzen 5.
          so nothing special. quadro is only needed if you do assemblies with more the 200 parts (i go regulary over that with my card without many issues) fusion is just not optimised since its a hobby program. inventor gets all the good code massaging.

      1. OpenSCAD probably makes a great deal of sense for the holes, but would have been rather more effort for the actual Pi case, which was moulded round an existing 3D model of the Pi.

        To actually make the pattern by CNC machining you don’t need to model it at all, a few lines of hand-coded G-code would do the job.

        ;drill cycle with dwell
        G99 G82 P1 R0.5
        #99 = 6 ; spacing
        #1 = 0
        O100 REPEAT 20
        #2 = 0
        O200 REPEAT 20
        X[#1 * #99] Y[#1 * #99 * SQRT[3]]
        #1 = [#1 + 1]
        #2 = [#2 + 1]
        O200 ENDREPEAT
        O100 ENDREPEAT

      1. Oh come on!
        I see this as just the start of a (w)hole new series like #badgelife

        In fact, I see the possibility of incorporating the Cheese Grater into a series of “badges”!

  2. Has anybody tested how hard the cheese grater grill is to clean? (How much it tends to collect dust, how much dust blocks it up, how hard to get dust or dust & grease & hair out of it.)

    Or is this one of those things where you keep it covered up all the time so it will look nice.

    Wonder if Apple sells just the case for the looks.

    1. Apple sells everything for the looks. It’s so typical that they’ve finally made a halfway decent pro model for people who actually use their computers for important things, and it’s modular and upgradeable, and it won’t overheat because it’s not all stuffed into a toilet paper tube… But yeah, of course people are geeking out about the fan grille? Wooow cooool, wish I could un-tick that box on the order form and save some money on the silly over-engineered case and just put it in a cheap Antec or something.

      I mean it’s really telling that the part everybody won’t stop talking about is literally the facade, and the (incredibly expensive) introductory model only comes with a 256gb hard drive. I’m sure it’ll be a proprietary SSD so you can’t just put in your own that you’ve bought separately, you’ll have to get the $12,000 model from Apple isntead. Pretty obvious that they’re anticipating plenty of users to buy one just for the sake of conspicuous consumption and use it as another facebook machine.

      1. I worked out in another thread that the machining time fo the grille is about $5 at job-shop rates (based on 3 holes per second). Weigh that against an extra part for a more generic grille and it might even be cheaper than some other options.

        But I admit, I bleed in stripes :-)

  3. I stopped the video when he said that you can’t place a sphere on a point, opened Fusion360, and modelled it out in about 5 minutes by placing spheres on points.

    Summary (as I am too lazy to make a video): sketch with a pair of equilateral triangles. Edge length I used is 2,5mm. Place points in the sketch at the intersections (since there MUST be a point for easy pickup… ends of segments and intersections are tough). Find the center of a triangle using construction lines and drop a point there, as well, to project to the second face. Draw a rectangle for the solid extrusion on the same sketch.

    Extrude the rectangle to 1.1mm thick solid. Place two 2,0mm spheres on adjacent vertices from the sketch, and construct them as cuts. Then rectangular pattern to fill the face, selecting the two hemisphere cuts as the feature, ‘SPACING’, rather than `EXTENTS’ as the descriptor, and using the measure option for the spacing in both directions. As many repeats each way as needed to fill the region.

    Project the point at a triangle center to the other face and use it as a triangle corner to do the same thing.


    1. You can place a sphere on the plane centre point. But you can’t tie one to a sketch point. You might think you have (I did, this was the first thing I tried) but if you try changing the size of the triangle in the sketch you will find that the spherical cut does not move with the sketch.
      It appears that you can edit the temporary sketch that appears, project your original point to that and then create a sphere on that point. That does give accurate placement, but the spheres still do not move of the underlying (d5 in the demo) dimension is changed.

      Now, as you _can_ tie a sphere to the plane origin you could make a very small array of just one copy of the first hole (I thought that move/copy would work but you can’t move/copy features and whilst you can select the cut as a “face” there is then no option to “make a copy”)

      Reference to the problem of placing spheres:

      This is quite an old thread, but the behaviour is the same today, you will see that a temporary sketch appears that does not contain your carefully placed points.

  4. For something like that Pi case, simply set it up as a set of circular pockets for each side, with the cut on the tool centerline. Use a center cutting ball end mill slightly smaller than the pocket diameter so it can circle around and plunge down in steps. No need to model spheres or 3D model the whole part.

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