ForumTouchy Subjects ► 3D projection question
Y-up or Z-up?
  
Y up.
  
X up
  
Y-Up. In 2D, X is horizontal, Y is vertical, so Y up. Z is depth, perpendicular to the 2D screen plane. Really makes no sense to start redefining Z as up when you move into 3D as if you suddenly started looking down at your monitor from above.
  
I assume the convention came from working on paper, where it makes more sense to have the plane be in that direction
  
I can *maybe* see that if we're talking about architecture, but I can't think of anything else you'd draw top-down on paper, and the fact that the paper's usually lying down on a table doesn't make any difference for what you're drawing on it. I'd think most people would default to a drawn object "facing" them along the -Z axis, making Y-Up again.
  
im gonna start talking in w(゚Д゚)w

why isn't this thread in technical corner o(≧口≦)o
  
im gonna start talking in w(゚Д゚)w

why isn't this thread in technical corner o(≧口≦)o


because the Desmos discord showed me that this sort of thing can get really political
  
Z-up because that's how quake's engine and source engine does it. I played a lot of those games and got used to it, so I won't bow down to the y-up heathens.
  
Z-up because that's how I learned it in multivariable calc. Imagine converting to cylindrical coordinates and having (r, theta, y) instead of (r, theta, z). Absurd. Minecraft has done a decade of work to soften me to the y-up perspective though.
  
Z-up. Minecraft is an abomination for brainwashing innocent children into using the inferior Y-up style.
  
I've never seen a game engine that uses Yup other than Minecraft. Everything in 3d Calc and most games has Z as the vertical axis.
  
just playing devil’s advocate here, but since 2D math points the y-axis up, wouldn’t it be more logical to just draw another axis penetrating the plane at the origin rather than rotating the plane and then putting the axis?
  
I like Y-up because that's how it is in math, and I haven't learned it any other way.
  
E7 said:
I've never seen a game engine that uses Yup other than Minecraft. Everything in 3d Calc and most games has Z as the vertical axis.

...You've never met Unity? Or Godot?
  
The ace attorney character?
  
Every time I see this thread I think it's talking about actual projectors being mapped onto a 3D surface and I'm excited to talk about that and then I remember it's an abstract maths question thread and then I'm sad.
  
Well damn. So did I.
  
This sandbox/projector combo is kind of like that.
  
By "up" we mean "the direction against gravity", right?

If you're generalizing The Legend of Zelda to 3D, then z is up. If you're generalizing Zelda II: The Adventure of Link into 3D, then y is up.
  
e-bag said:
I like Y-up because that's how it is in math, and I haven't learned it any other way.

I'm assuming you're talking about 2D mathematics on a plane, right? Just curious
  
ye
  
Mathematics doesn't care. And Y isn't up in your graph there, or at least the same type of up. Add a Z onto that graph of yours. Some people will declare y = f(x,z), others z = f(x,y).

Although taking a stroll through what online graphing calculators say, I mean this is t exhaustive and may not be representative, but I only see Z-Up in these very strictly math-oriented utilities.
  
Thinking about it more, honestly I'm starting to warm up to Z-up. Mostly because it makes more sense to have z=f(x,y) than to have y=f(x,z), and it makes sense to have the vertical axis be the output of the function.
  
I personally go with z-up as the right hand rule has kept me with that standard for a while.

I also heavily vibe with coordinates on a map be listed in (X, Y) coordinates, with the vertical direction declared as Z.
  
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