this post was submitted on 06 Jul 2023
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[–] [email protected] 9 points 1 year ago (3 children)

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.

[–] TwilightKiddy 15 points 1 year ago (4 children)

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] 7 points 1 year ago

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

[–] [email protected] 3 points 1 year ago (1 children)

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] 2 points 1 year 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] 1 points 1 year ago (1 children)

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.

[–] TwilightKiddy 3 points 1 year 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.

[–] [email protected] 1 points 1 year 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] 4 points 1 year ago* (last edited 1 year 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] 3 points 1 year 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...! :-)