• croobat
    link
    82
    edit-2
    11 months ago

    I found this handy reference a while ago. But yeah, we are kinda screwed.

  • @[email protected]
    link
    fedilink
    1611 months ago

    I work in 3D metrology and the consensus is right handed and Z up. Had no idea left handed existed!

    • @[email protected]
      link
      fedilink
      411 months ago

      How does projection work in your field? X, Y, Z get converted to X, Z and 2D screen planars have no Y axis?

      Who invented this, why did she do it and where to send my official letter of complaint?

      • Pelicanen
        link
        fedilink
        511 months ago

        I thought right-hand rule with Z up as thumb was standard in science? You usually project on the xy-plane, for example when calculating the distance to objects on a flat surface.

        • @[email protected]
          link
          fedilink
          211 months ago

          I only know thumb = motion/current but now since you say, it’s clear: people used x/y for 2D logically but the 2D plane used to be paper. which is parallel to the earth surface (usually). Computer screens are perpendicular so Y points up, not away from you.

          So this makes sense with paper, TIL. With computers, Z traditionally means depth.

      • @[email protected]
        link
        fedilink
        111 months ago

        TBH I’m not sure I totally understand the question but projection is very useful to decompose the orientation of elements, like a cylinder that you just measured with a machine or a scanner. The coordinates and orientation (angles) can be projected in the three main planes XY, YZ and ZX.

        • @[email protected]
          link
          fedilink
          2
          edit-2
          11 months ago

          Sorry for being unclear, I was talking about screen projection. For actual visualization.

    • Kogasa
      link
      fedilink
      311 months ago

      This can happen if you accidentally pilot your player character into a singular linear transformation.

  • Buck Fucket
    link
    911 months ago

    Ugh, when I have to open CAD for a project at work I have to setup a new coordinate system with Z going up, every time. The engineers just work with Y up for some reason. Too lazy to change it perhaps? Solid works and Inventor default Y up? I’ll never understand it. I definitely understand this meme. There’s also models with an origin 10 feet off in X and 20 feet out in Y. I just do not friggin get it man.

    • @[email protected]
      link
      fedilink
      1511 months ago

      Because math works with Y up. Physics steal from math, engeneering steals from physics, so, here you are.

      What I can’t get is imperial measurement system. Apparently, nobody but americans can. And that stuff is far worse than Y and Z switching places.

      • @[email protected]
        link
        fedilink
        711 months ago

        as a minecraft player learning how to use autocad, i thought y up was alot more ubiquitous then it apparently is

      • @Widowmaker_Best_Girl
        link
        311 months ago

        That’s what I don’t get. Why would they make Z up when in algebra, Y is up. It’s all based on math, shouldn’t we keep consistent on that?

        • @[email protected]
          link
          fedilink
          210 months ago

          Because the z axis is represented as an extension of the xy-plane, coming out of the paper essentially, so we represent it as up

      • @[email protected]
        link
        fedilink
        111 months ago

        What I can’t get is imperial measurement system. Apparently, nobody but americans can

        I’m not American but I’ve been living in the USA for ten years and I still have trouble with imperial measurements. It’s painful dealing with fractions of an inch instead of millimeters.

      • @[email protected]
        link
        fedilink
        110 months ago

        That’s not true though. While there isn’t a standard, convention is to have z up in mathematics, as z is extending the xy plane we normally work with into a third space.

        • @[email protected]
          link
          fedilink
          310 months ago

          Might depend on where you were learning.

          On paper, when I was learning Descartes’ coordibate system, we used Y as up and X as left-right. And when it was time to plot in 3D, we used Z to “extend” the plane into yourself and away from yourself.

          You just hold your sheet of paper perpendicular to the ground (or just use a whiteboard) and it all makes sense.

    • @amanaftermidnight
      link
      4
      edit-2
      11 months ago

      CAD used to be digital abstraction of the physical media that is 2D drawings on paper, so XY is the plane of the paper going horizontal/vertical, and most detailing are in vertical cross sections so Y ended up being up most of the time.

      The Z axis is then Frankensteined into the existing system to get a proper 3D representation, so it became the depth axis for the existing XY plane.

      In Minecraft it’s even more evident as Notch Frankensteined the Z axis into a game engine that’s originally developed for side scrolling.

    • @[email protected]
      link
      fedilink
      311 months ago

      In which world should Z point up and Y represent depth?

      Totally crazy opposite world, where cats hunt dogs and rain goes up? This is plain evil…! :-)

  • @MooseBoys
    link
    811 months ago

    Nobody commenting on the chirality difference…

  • @[email protected]
    link
    fedilink
    8
    edit-2
    11 months ago

    It gets more cursed the more you look at it:

    • you have to convert the coordinate axes (swap z,x,y)
    • then you find out the right/left handed is flipped
    • now your brain melts if you even try think how to solve this with transformation/rotation, what ever.
  • @[email protected]
    link
    fedilink
    511 months ago

    In robotics I use right hand coordinates with z up. So a car is moving in the 2d xy plane and z is the optional third component. This makes sense to me. For some kind of painting on the screen I can understand why you use y as up. Then again, I know these as uv-coordinates.

  • Eh-I
    link
    511 months ago

    Fuck it, the world is sideways now.

  • deaf_fish
    link
    fedilink
    411 months ago

    I feel like the cat’s coordinate system needs to be rotated 90° to the right.

  • TurretCorruption
    link
    311 months ago

    And this is why you always export for the software you intend to use it in.

  • Tabboo
    link
    211 months ago

    UCS rotate