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View Full Version : X,Y,Z axis: Blender's mistake!

blenderman345
31-May-08, 08:25
:eyebrowlift2::eyebrowlift2:I haven't noticed any newbies or anyone mention this so I might as well. As you may notice in any 3d app, or any standard math:D Y is up, Z is back and X is the front. However in Blender: X is X, Z is Y, and Y is Z! But if someone noticed it they probably didn't say because, then you'll be mixed up in Blender!

WWM
31-May-08, 08:34
It's been brought up many times. You can either look at the XY plane as being a on a wall where Y is "up" or you can look at it lying on a table the way Blender does where Z is really up, since only 3D can possibly have an up.

Charlie
31-May-08, 09:02
It's been brought up many times. You can either look at the XY plane as being a on a wall where Y is "up" or you can look at it lying on a table the way Blender does where Z is really up, since only 3D can possibly have an up.

That's exactly how I imagine it.

Gwenouille
31-May-08, 09:14
Oh yeah i've never thought of that... What difference does it make anyway ?
I find it absolutely fine and natural this way: to me a plane is described by X and Y and is horizontal. Z is altitude.

I didn't know that other 3D apps did it the other way round....

Some day they'll have to adapt ! :D

Felix_Kütt
31-May-08, 09:23
the standard math i was teach had z up, guess my teacher must have been weird or something.. :S

though yeah, the right hand rule, or z up is more used, or used to be atleast, in CAD,
and y up in most "traditional" 3d apps, the last is the case probably mostly because in the 3d camera, the z represents depth,
both work, the only weird thing really with blender is that for bones, from what i understand y is the length/"up". :confused:

toontje
31-May-08, 10:01
Is that a natural law? Or is it a mathematical agreement?
The Z-axis being the depth of the monitor was a marketing gimmick to warm up the audience during the early rise of 3D. Besides, both coordinate system works. Their are not broken. One is left handed, the other is right handed.

delic
31-May-08, 10:06
z up is a standard "map" way to represent 3d space where x,y represent the plane and z the height, most apps use that, and z depth is a "camera" way, like in maya I think .

nfollmer
31-May-08, 10:07
DirectX and OpenGL differ this way as well. I forget which is which though. No big deal really, just rotate your model before export if whatever else your using doesn't like the axis set like that. :)

JohnnyThunder
31-May-08, 10:57
3ds Max and UT both have it set up the same way as blender.

Orinoco
31-May-08, 11:33
In future, you might want to do your research before posting "Blender's mistake!" at, of all places, a Blender forum. :no:

free_ality
31-May-08, 11:37
Well I did notice that whenever to export to an .obj file(wavefront or whatever) it ask you If you want to do the 90 degree rotation to match up with other programs up and down. I dunno though, It hasnt mixed me up really, except for a couple slip ups when Im animation with IPOs.

Ace Dragon
31-May-08, 13:00
Uh, I thought I note that I move an object up on the 'Z' axis in Blender.

Maybe it's local coordinates you're seeing?

jdk1.0
28-Jul-11, 12:42
Is that a natural law? Or is it a mathematical agreement?
The Z-axis being the depth of the monitor was a marketing gimmick to warm up the audience during the early rise of 3D. Besides, both coordinate system works. Their are not broken. One is left handed, the other is right handed.

Whatever crack you're on, I want it! In the beginning, back in the 1960's when graphics were being invented there was no such thing as 3D. Everything was 2D, and the whole world was monochrome. There was no "gimmick".

Z-depth has been around for many years, it stems from the fact that we use our monitors like a picture on the wall, not laying flat on the table. The XY plane corresponding to the monitor is a natural way to view a 2D cartesian coordinate system. The natural extension to this is to have Z "into" the screen.

The Maths views it a different way. The XY plane is a flat sheet of paper on the table. Z comes right up off it and into it. Hence Z-up.

Left and right handedness isn't really the issue here. That just denotes the order of the axes.
I can choose X-up, left-handed convention, or Z-down right-handed, or whatever I feel like. It all depends on how we learned it or what standard we happen to be using at the moment.

arexma
28-Jul-11, 12:52
Whatever crack you're on, I want it!
...
Left and right handedness isn't really the issue here. That just denotes the order of the axes.

Good way for a first post to start insulting folks :D

And actually the handedness is the ONLY thing that matter, everything else is unintresting. You can call your axis Adolf, Cupcake and Zebulon if you like, all that matters is to know where it is positive and negative, else you´ll never get anything working.

However I doubt anyone cares after 3! years.

aermartin
28-Jul-11, 18:05
I would code Y up just to shut up these kinds of threads.. Z-up, Y-up as settings in user prefs.

Uncle Entity
29-Jul-11, 07:39