XYZ Reference Frame

thingiverse

I spent two full days at work trying to solve a problem around a sequence of 3D rotations that had me stumped. It wasn't until I grabbed a piece of equipment with X, Y and Z axes etched on the casing and took it through the desired sequence of rotations that I realized what my (extremely simple) problem was - one of my rotations was inverted. It was that easy, but until I had something in my hands to prototype the rotations with, I couldn't for the life of me get it to make sense. That afternoon, I whipped up this little thing and have already printed off one for the desk of everyone in the office because none of my colleagues spotted the error either. It's just a simple little toy with X, Y and Z axes in their correct relative orientations that you can pick up, inspect, and turn around. Maybe hold it up to a screen when you're working on image processing and wondering why all your depths are coming up negative. Maybe hold it in front of you as you try and figure out why an inertial system uses North-East-Down as its X-Y-Z reference frame. Tape it to your arm to try and understand why your character's elbows keep bending backwards. Maybe just stand it on its three legs on the floor and jump up and down on it until it's flat to relieve some of the stress that comes from dealing with any 3D reference frame rotations. In all seriousness, this has replaced my debugging rubber ducky on my desk, and I highly recommend anyone else out there who works with 3D rotations on a regular basis give it a try. You can also use it as something of a calibration test; here's a list of the easy-to-measure dimensions: * X, Y, Z boxes: 10mm cubes * Axis shafts: 6mm OD cylinders * 'Origin' ball: 20mm diameter sphere * Hollow Walls: As per file name (1mm or 2mm), can be picked up at the top face of the axis cubes. Print orientation is up to you. If you really want it to be a true reference, then I suppose it should be printed axis-aligned with your printer. I printed mine with the ball facing down and all three legs up in the air. Took some cunning support material, but the 2mm wall one came out nicely. Photos will come on Monday when I'm back in the office.