Why is Blenders Orientation Different?

Can someone please tell me why Blender uses a different orientation than the standard one used in all other applications and can I change this in preferences?

Standard:
X = left to right
Y = up and down
Z = forward and back

Blender:
X = left to right
Y = forward and back
Z = up and down

Y up isn’t standard, Z up is pretty common (EG Unreal Engine works that way, so does Zbrush, as well as most CAD software). Personally I think Z up makes a lot more sense (it makes sense for the up axis to be the “separate” one, rather than one of the horizontal ones) but obviously that’s opinion.

As far as I know you can’t change it in the preferences, although most exporters I’ve used will allow you to set the up axis so the models will still be compatible with Y-up software without having to manually rotate them.

It is a bit confusing that Y is the up axis for bones though, not sure why it’s different there.

what @Captain Oblivion said is true !! moreover even in math and physics Z is for up and down !!

suppose you are in front view in viewport
when you look you see Z-X which is the front of a cube

when you look on top of that cube you have the standard XY axis plane

coordinate system is a right handed one!

might need some getting use too but after a while is it logical

would also like to know why for bones then Y axis is used a up axis!

but I now prefer that system and it is logical now

happy bl

Because the mathematical convention in Cartesian coordinates is Z is up. Has been for a long time.

In 2d space where we are thinking of a plane Y is conventionally the second axis.

I guess it depends on how you are thinking about it. Is the screen an analogue of a piece of paper held vertically or a window into a 3d space?

come on, it’s blender!
we select things with right click, after all… :no:

Right click is for pen & tablet, re-set if using mouse. Or not.

An analogy.

"Was a kid then.
Sitting in a classroom. Learning math, geometry… watching around. Absorbing…
Had a notebook on a table. Everything i got used too was correct, the norm. Looking into the book from the top. We learn from books.

Was a kid then.
Sitting on a rock. Learning calculus, trigonometry… looking around. Absorbing…
Were drawings on the ground. In dirt. Gazed at stars above. All was as it was meant to be. Walking front and back, left and right. My world was flat.

Today i gaze into the future, front. There are teachers, media, prophets telling me how to live. So much false science in between. Unconsciously, this present have got me stirred, confused… all mixed up. Got used to just watching, same as many others… became apathetic.
So I took on blending and rediscovering it all and have realized, even the coordinate system was rotated. All in favor of me staying dumb. To be left for a number in the system, a cog in the machine, a sheep for wolves, a fish for sharks…

Yes, i started blending and suddenly found my way to the roots."

Just Google “y axis is vertical” and you’ll see how common it is to have the Y axis as the up and down axis and Z axis as front to back.
I still think it’s all backwards according to what were taught. In school children are taught that “X” is left to right and “Y” is up and down.

When I am facing a 3D viewport in After Effects I place image planes from front to back along the “Z” axis. So why should it change in 3D. It makes more sense to keep it standardized IMO. You are told to place objects in Z space or anther words stacked from from to back.

After Effects

By default, layers are at a depth (z-axis position) of 0. In After Effects, the origin of the coordinate system is at the upper-left corner; x (width) increases from left to right, y (height) increases from top to bottom, and z (depth) increases from near to far.

https://helpx.adobe.com/after-effects/using/3d-layers.html

Maya & Unity
Y is the default up axis for Maya

The Cartesian coordinate system in two dimensions (also called a rectangular coordinate system) is defined by an ordered pair of perpendicular lines (axes), a single unit of length for both axes, and an orientation for each axis. (Early systems allowed “oblique” axes, that is, axes that did not meet at right angles.) The lines are commonly referred to as the x- and y-axes where the x-axis is taken to be horizontal and the y-axis is taken to be vertical.

Y-Axis

  1. The vertical axis of a two-dimensional Cartesian coordinate system.
    http://www.thefreedictionary.com/y-axis
    Horizontal and vertical lines
    http://www.mathsteacher.com.au/year8/ch15_graphs/05_hor/ver.htm

I guess it all depends on how you look at the 3Dplane. I prefer to look at it from the front or camera view in Blender which is on Blender’s Y axis where x=left/right and z=up/down, which I find confusing. But in Blender if I look at the 3D plane from the top, then it is correct, where: x=left/right and y=up/down so I guess it depends on how you look at it. Just wish there was a standard out there. :slight_smile:

why then in Blender pass of the depth is called Z? it should be named Y then :slight_smile:

Not an original question !

“Y” is the vertical axis (if you want to see it so) in 2D. “X” and “Y” form a plane. You think on the surface of a table as this “X” and “Y” plane. Then when you add the third dimension in the space with the “Z” axis you add volume, that is you add infinite parallel planes to that original plane you have (the table surface) up and down. It’s just a convention, but this is the typical way to teach it and that’s why the Z axis is usually represented by the vertical direction.

AutoCAD, the most widely used CAD app, Autodesk’s flagship which made them amassed tens of software, that included Maya, Max, XSI, etc., have always used Z-up from the very beginning. So what makes you think Y-up is the only mode that can be referred to as standard? Both can be made standard.

Z-up makes more sense to me because most things start from the ground, which means the zero starts from there, then up in positive direction, in the air, up up and away… :smiley: As opposed to Y-up’s imaginary zero.

Autocad was autodesk’s first acquisition. They actually started as a desktop PC company, and autocad (made by a 3rd party) was the best selling product on their platform. They didn’t even code their own flagship.

sorry, off topic, but historically interesting!

on topic:
Some programs use y-up, some use z-up. There is no standard.

:slight_smile: I just can’t resist mentioning Autocad because most floor plans are done in it. So you better demand that your other app find a way to adapt to it, not the other way around, if you’re into interiors, buildings… so that importing them would not be a problem.

Yeah, I work in autocad and blender at work, and once I got past some eccentricities in how autocad exports .stl files, it does import pretty smoothly.

Standard:
X = left to right
Y = up and down
Z = forward and back

Blender:
X = left to right
Y = forward and back
Z = up and down

This is completely wrong, there is no “left” and “right” in 3D world-space. You’re mixing this up with image or camera space, in which case Z is depth and X and Y are horizontal and vertical respectively - that’s how it works in Blender’s compositor/shaders too.

The misguided idea to define world-space “up” as Y comes from this egocentric view that the world doesn’t exist outside your narrow field of view. This may actually be true for painters, directors or stagebuilders, but the godlike worldbuilders look down on the scene, where their puny subjects are moving primarily along two axes - X and Y.

Ask yourself, would you rather be a painter or a god?

When I am facing a 3D viewport in After Effects I place image planes from front to back along the “Z” axis.

After Effects is for compositing, not for scene modeling. Blender’s compositor actually uses the same convention as After Effects.

So why should it change in 3D.

Because those two coordinate systems don’t match at all, unless your camera points into a very specific direction.

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Yeah, I brought up this issue with Campbell in the “ask the developers” thread to see if there was ever going to be a Y-up option. The answer was no, so it is just a matter of getting used to it. Even though Blender was the first 3d app I ever tried about 15 years ago, I still prefer Y-up , as most non-CAD 3d apps and compositors use it, whereas CAD/CAM always has Z-up. Max and Blender are the odd ones out, while Maya, Houdini and Modo give you an option to use either , which is the ideal scenario!

Also, some applications like C4D use a Y-up left hand implementation(Z positive goes into the screen) whereas most use the right handed one. In the end, there is no superior system, just a matter of what you are used to. The hardest thing is when animating and jumping between applications that use a different implementation, it can do your head in :slight_smile:

I’m pretty sure similar gasps were heard when contemporaries were informed of the Copernican world view that had the sun at its center - it just wouldn’t fit the mental model of the audience! (a model which for some people persists to the modern day)

I’m glad that Blender uses the standard convention that is universal in engineering applications, instead of the non-standard convention that is unfortunately pervasive in CGI. To be superior sometimes means being at odds with the expectations of the unwashed masses. It can’t be helped!

My oh my, how little people need for happiness. A letter to mark their direction…

Seriously, all these recent threads and posts. C vs C++ vs world, Y vs Z. Makes one wonder.

I always laugh when people bring this up. I use 6ish different 3d packages. Some use Z up, some use Y. Not one have I ever had a problem remembering which is which.