Is it possible to make Blender a Y-up world?

Question

After learning bits and pieces of Maya, 3DS Max, IMAGINE and XSI I noticed that they all have Y-up worlds with Z being used for depth (naturally).

is there a way to make Blender a Y-up world? and does anyone know why isnt it Y-up in the first place?

would be interesting to find out from Ton himself why he went with Z up. — zeffii, May 30 '13 at 07:04
I think 3DS Max is actually Z-up as well. The reason is explained well here. — grc, May 30 '13 at 07:06
Tips for Unity Game Modeling in Blender The link above is what I keep in mind before starting any Blender project I know that will be used for Unity. — Nate, Jun 02 '17 at 05:04

score 42 · Answer 1 · edited Mar 08 '23 at 20:30

42

As far as I know, cannot be changed. .

Blender uses the right hand coordinate system with the Z axis pointing upwards. This is common with the coordinate systems used by most common 3D CAD packages and 3Ds max:

enter image description here

Another reasoning for this is that a common convention for real world applications for engineering and science is that X and Y axes define a flat ground plane while the Z axis defines up and down

enter image description here

However, if you work between these software that you mention above, one way you could maintain consistency is to export the object(s) as a .obj or .fbx (or any other similar format, most if not all exporters in Blender have this option) to the other application with the 'up' axis being Y etc.

enter image description here

edited Mar 08 '23 at 20:30

Crantisz

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answered May 30 '13 at 07:04

iKlsR

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hmm. so the Z-buffer is really a Y-buffer ? :) – user232 May 30 '13 at 12:27
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@user232 - No, that is camera coordinates where x and y are on the image plane and z giving the depth. – neil Jun 21 '13 at 14:32
This is NOT unique to Blender. https://twitter.com/FreyaHolmer/status/1325556229410861056?s=19 – L0Lock Sep 26 '21 at 20:16
Software can still use a right hand coordinate system while defining the ground plane as either XY or XZ. I see right-handed vs left-handed as a separate issue. – prideout Nov 03 '23 at 14:37
I think I may have misunderstood the X and Y planes. As far as I understand, X and Y represent the horizontal and vertical axes, respectively, in a 2D canvas. Therefore, it seems logical that the Z axis would represent depth, which is why we use the term "Z-depth". However, I am curious to know why Maya uses the Y-axis as the up-axis and the Z-axis as the depth axis, while others use Z as the up and vice versa. Additionally, the term "Z-depth" itself represents depth in the 3D world. – pixelngrain Jan 31 '24 at 07:53

score 12 · Answer 2 · answered May 30 '13 at 14:15

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It's obviously not perfect, but here are a few things that will make Blender "act" like Y is up.

Navigation
You could change all the shortcut keys so that Y was sort of the top.

Gravity
Change Gravity to Y direction:
gravity direction

Grid
Finally, remove the grid floor and only show the x and z axis when rotating the view.

answered May 30 '13 at 14:15

CharlesL

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You should probably rotate the camera too, while you're at it. – Gwen May 30 '13 at 15:01
where is the Grid Floor option? – rraallvv Jun 22 '13 at 00:08
In the properties panel (N). – CharlesL Jun 22 '13 at 12:58
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This answer should be higher up, it at least adds some workarounds that might be useful! – Ludwik Jul 19 '15 at 14:16

dwelle · Answer 3 · 2013-05-30T07:17:38.490

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Blender is based on Cartesian right handed system, which is Z-up. From what I've read it's not possible to change that since it's pretty much hardcoded among Blender's various features, but I may be wrong.

edited May 30 '13 at 07:17

answered May 30 '13 at 06:51

dwelle

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you're wrong, you can have an Y-up right-handed coordinate system, or any-up for that matter. – user1095108 May 21 '18 at 01:33
Can you supply source? I haven't used blender for some time now, but I recall it wasn't possible back then (but then, I haven't supplied source either). – dwelle May 21 '18 at 17:54
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Where in math has anyone heard of Y-up (or down, for that matter)? The proper criterion for a right-handed coordinate system is the result of the cross product (z = cross(x, y), x = cross(y, z), y = cross(z, x)), it does not matter at all which of the unit vectors (x, y, z) points "up". – user1095108 May 21 '18 at 18:05
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You can have right-handed with Y being up as well as left-handed with Z being up. They are not mutually exclusive. Godot uses Y-is-up and right-handed. Here's a chart: https://pbs.twimg.com/media/DTbWux8WkAUOZZx.jpg:large – Aaron Franke Dec 08 '18 at 07:35
@AaronFranke good point – dwelle Dec 08 '18 at 18:41
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@user1095108 True, but the majority of users of the application are not 'In math'. They are looking for functional convenience, not abstract truth. :) – Robin Betts Mar 03 '23 at 18:39

score 0 · Answer 4 · answered Oct 15 '22 at 11:59

You may "correct" the vision (on your screen) by rotating the camera, but the more important thing is the calculation of transformations and rotation in particular. They all use coordinate system as Z -up. For example for rotation it uses XYZ as default. I am not sure if you can use XZY and watch your transformations accordingly.

Yes there are Y-up systems, but they are more related to computer graphics histoy rather than maths. When there was only 2D on computer screens, X was the horizontal, and Y was the UP axis. When the third D was added, computer people chose to continue with this and added Z forward, off the screen. But they use their transformation matrices accordingly.

Is it possible to make Blender a Y-up world?

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