THE GRAND Y/Z DEBATE 2005!!

Discussion about everything. New games, 3d math, development tips...
Midnight
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THE GRAND Y/Z DEBATE 2005!!

Post by Midnight »

Ok the subject pretty much says it all and for those that don't have a clue here's the story.

Back in the day when autoCAD or "automated computer aided design" was produced it was given x,y,z coordinates where x was width y was depth and z was height.

And I only speak for myself but I was taught in school that z is the height axis.

However I have heard people claim this is incorrect and that autoCAD set a bad standard for everyone else and there has been debate ever since.

Although this is probably the deepest conversation about it since they are just algebraic pseudovalues that merely give name to true dimension in a much more compact form.. an abbreviation if you will.

I just want to know where people stand on this subject in Michigan schools z is height now Irrlicht uses y so does that mean in Austria they teach that?

I happen to be related to a machinist and long time user of autoCAD and other 3rd dimensional drawing software that will punch my lights out if I say y is height enough times to his face.

So you tell me.. which is correct?
does it even matter?
how many others are bothered by the potential bugs caused by incompatible programs?
shouldn't there be a concrete standard on this subject?
Robomaniac
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Post by Robomaniac »

in all the engines i've used (irrlicht, neo, cs, and ogre), it's been x = width, y = height, z = depth. That's also what i've learend in all my math courses
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area51
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Post by area51 »

I'd agree with Robomaniac.

In 2d you have X and Y co-ordinates (width & height), which leaves Z for depth (ie Z-buffer).

X, Y, Z

It cant make sense any other way.
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Last edited by area51 on Tue Feb 22, 2011 1:08 pm, edited 1 time in total.
darkraven
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Post by darkraven »

That's some funky schooling. Any application I've learned on whether its 2d or 3d has had the x co-ordinate going right and left and the y co-coordinate going up and down and the z was added to make an object 3d.
Midnight
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Post by Midnight »

If you consider y height then yes.

But before computers were mainstream and in the real world z is height.

Maybe I was learning it in school before the standard had been changed to uniform for computer technology.. but autoCAD was one of the first graphic tools and it used z for height and possably still does.

I took drafting in highschool aswell and we did it with z then also.
When I first started using Irrlicht and modeling tools like blender and milkshape and 3ds max and maya I noticed it was y but paid little attention.

I suppose this with forever be debatable but it's obvious that y is now the new standard for height.

I'm just curious if anyone else remembers z as height?
CapBBeard

Post by CapBBeard »

Yeah, x is width, y is height, z is depth.

I think right and left handed coordinate systems is more what you should worry about. Check out RenderMan and pay particular attention to the Z axis ;)
Midnight
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Post by Midnight »

It's always been x,y,z

but the definitions of depth and height were held loosly.. in 2d depth is height and height is depth it makes no difference because its 2 dimensions instead of 3.

I find it hard to believe my momery is false and that somebody that has designed the machines that we all use today for the past 20 years could be imagining this.

I might do some research into this its rather interesting to me.
Midnight
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Post by Midnight »

CapBBeard wrote:Yeah, x is width, y is height, z is depth.

I think right and left handed coordinate systems is more what you should worry about. Check out RenderMan and pay particular attention to the Z axis ;)
oh good point..that could very well be the base of our confusion.
X_for_Extra
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Post by X_for_Extra »

If you do maths on paper or deal with stuff like that, the intuitive conversion is to imagine a paper with a diagram lying on your desk. Z then becomes height.

But in the world of computer games, programmers usually start with 2D games projected on an upright screen. The intuitive conversion then becomes to add the 3rd dimension at a right angle to the face of the monitor. IE depth.

So its all about how you learned to visualize the 3rd dimesion.

As for what to use..getting the game world to swap is probably impossible at this point.
Should put something witty here I suppose.
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Post by AutoDMC »

In my math classes, I was taught that x went (0 -> Infinity), Y went (0 ^ Infinity), and that Z went through my paper (kinda like my pencil when things didn't go right!).

When I started using 3dStudio Max, I noticed that Y and Z had been knocked about.

When we look at a computer screen, we see X is left and right, Y is up and down, and Z is the "depth" into the picture tube, like my math class.

But 3dsMax comes from the Cad world, and in the Cad world (according to my 3dsMax teacher, Mr. Nugent), you would draw a blueprint as 2d shapes on the screen in X and Y... then you would "lay the sheet down" on the ground in the 3d part, and EXTRUDE you walls and etc. into the Z dimension.

Think of it as building a model's shape in Illustrator (X and Y), then extruding those shapes into depth (Z) in your 3d package, and it really makes sense.

Sense the points and vectors in your original Illustration take X and Y coords, theres only one dimension left, if you don't want to flip the coords around in your original draft, eh?

I've never really cared about the orientation of Z, really. It's the blue arrow on the gizmos in 3DS Max, and I'm building the world the way I see it, not by pen and pencil, like the 3d stuff in "Tron." And if my world gets wonky in the rendering package, I just rotate everything 90 degrees around the X axis, and everyone is happy :D
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Re: THE GRAND Y/Z DEBATE 2005!!

Post by niko »

Midnight wrote:I just want to know where people stand on this subject in Michigan schools z is height now Irrlicht uses y so does that mean in Austria they teach that?
I don't remember what they teach, but I just did it that way because it felt right. :)
Bolshevik

Post by Bolshevik »

X, y, and z have always been width, height, and depth, respectively, in... Everything I've ever done concerning 3 dimensions. I think AutoCad has z as height because the program is suppose to represent a diagram drawn on paper in three dimensions. In other words, since paper lays flat (I think someone mentioned this), they would add height, and since they already had x and y, z would've been the logical choice. Although, a, b, and c would be the same thing... It could be mouse, cat, dog for that matter, it's just de facto as far as I know.
Midnight
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Post by Midnight »

Bolshevik wrote:X, y, and z have always been width, height, and depth, respectively, in... Everything I've ever done concerning 3 dimensions. I think AutoCad has z as height because the program is suppose to represent a diagram drawn on paper in three dimensions. In other words, since paper lays flat (I think someone mentioned this), they would add height, and since they already had x and y, z would've been the logical choice. Although, a, b, and c would be the same thing... It could be mouse, cat, dog for that matter, it's just de facto as far as I know.
uh..whatever even in 3ds max z is height.

I think I discovered whats happening besides alot of confused devolopers.

in drafting it's length, width, and depth. there is no height.

x,y,z

honestly it doesn't matter much.. but pay attention you will notice this mixed up alot. and I don't know about you but is autoCAD and 3ds max and a 20 year vet machinist say that z is height then I agree with them not the other guy and a bunch of amiture programmers. :roll:
Midnight
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Re: THE GRAND Y/Z DEBATE 2005!!

Post by Midnight »

niko wrote:
Midnight wrote:I just want to know where people stand on this subject in Michigan schools z is height now Irrlicht uses y so does that mean in Austria they teach that?
I don't remember what they teach, but I just did it that way because it felt right. :)
More power to you and whatever your schools teach.

it's all phesudo anyways so it's not important I just find this subject interesting it's just another one of those things people will always disagree about because at some point on one side or the other someone didn't know how it was really ment to be.

Z will always be up and down in my world. but then again I live in yours. 8)
TheRLG
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Post by TheRLG »

The way I learned it in school was if you were looking top-down at a drawing on a piece of paper. X axis would be width of the drawing (usually right to left orientation) and Y axis would be height of the drawing(usually up and down orientation). Then Z axis came in, and was how far an object stood off the paper. idk, ive been taught every other way as well. for me, it all depends on how you look at it.
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