I'm confused about the axis functions in Blender. Basic algebra was many years ago, but the x was always the horizontal axis and y was the vertical, leaving the z for the 3rd, or depth, axis. Blender's xyz is yzx. This is not to be critical or trite; I was just looking for a logical reason that it was set up this way to help me remember it better :)

3dsmax and the Unreal engine use the same coordinate system, with Z being the up and down coordinate too. It all started with 3dsmax (as far as software coordinates are concerned). Released in 1990, the coordinate system change (from the norm) was designed primarily for architectural purposes. In Architecture, you typically start with your floor plan which would be plotted on a 2D grid first, X and Y. When it comes to extruding that up into a 3D model, you need the next dimension (Z) to be up. That's why 3dsmax used this coordinate system, as it was being used widely in the architectural design field.

In contrast, when Maya was released in 1998, it was being used primarily as an animation package. Animation at the time was typically in 2D, from side to side. Think early Disney animations, and some other old animated titles done from a side scrolling perspective view. You're looking at a screen, so the "world" of your animation is flat (left and right, up and down). You start working in X and Y, and your new dimension, Z, becomes the depth (INTO the screen, so to speak).. Many applications since Maya decided to use this concept of the coordinate system, which is why we see many applications after Maya using the 2D (Y = Up Z=depth) concept.

It's all about whether you are thinking in screen space, or in world space. In screen space (2D), Z makes sense as depth, given the XY screen coordinates. In world space, you would want to treat 3 dimensional objects as if they were real world objects, so the 3rd coordinate would make sense as up and down (because 2d is considered flat). I prefer to think of it this way too, which is why I like modeling in 3dsmax and Blender.

VolcanicMink

This is something unique to Blender as to the why not sure but most common I have come across are these reasons

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

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

I do not know if this will answer your question and hopefully someone else will chime in and maybe give a much better answer

Lobo3433 posted at 8:41PM Sat, 21 November 2015 - #4240153

VolcanicMink

This is something unique to Blender as to the why not sure but most common I have come across are these reasons

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

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

I do not know if this will answer your question and hopefully someone else will chime in and maybe give a much better answer

---

Looks like we posted around the same time. 3dsmax, Blender, and Unreal Engine are using the architectural concept of the Z space, because it makes the most sense for modeling, and most 3d software up until Maya used the Z=up World Space concept. This is the very reason I like modeling in Max and Blender. It makes more sense to me, but I can understand why it was changed for 3d animators.

Thank you. I remember stuff better when I understand the "why" of it! (The 3-year-old-WHY? stage never went away.)

This program and its tutorials are driving me crazy. It's as addictive as a video game.

It is funny I started to learn modeling on Hexagon which has the Y where the Z is in Blender and when I switched to Blender not sure why it did not phase me but if you wind up importing to like Daz Studio you have to use Daz Studios obj import option and select importing from Blender or the orientation will not be right same with hexagon if importing from Blender (not that there would be a reason why to do this) I do not have issues with importing to Poser from Blender but there are a few apps that it does make a difference. Just an FYI

Lux, there were lots of 3d software before Maya that used the z depth coordinate system. Maya wasn't the first to use it, and it wasn't "changed" for Maya. Cinema4D is one of the oldest, and first commercial 3d software, and came out only 1 year after 3dsmax for DOS. In 1991, C4D's first incarnation was released as FastRay, a software created around one of the first Raytracing render engines. In 1993, Cinema 4D v1 was released on the Amiga. It has always used the Z depth coordinates. This is well before Maya in 1998.

I agree that the Z=UP was adopted first by 3dsmax, because it was conceived from the CAD world, which had always used that 3rd dimension of building up from a flat surface, but I have to question the idea that Maya was the first to use the Z depth coordinate system. What about the software used in the 70s by Ed Catmull, who made the first ever computer generated animation? I'm sure it was using the screen space concept too.

SinnerSaint posted at 9:54PM Sat, 21 November 2015 - #4240158

Lux, there were lots of 3d software before Maya that used the z depth coordinate system. Maya wasn't the first to use it, and it wasn't "changed" for Maya. Cinema4D is one of the oldest, and first commercial 3d software, and came out only 1 year after 3dsmax for DOS. In 1991, C4D's first incarnation was released as FastRay, a software created around one of the first Raytracing render engines. In 1993, Cinema 4D v1 was released on the Amiga. It has always used the Z depth coordinates. This is well before Maya in 1998.

I agree that the Z=UP was adopted first by 3dsmax, because it was conceived from the CAD world, which had always used that 3rd dimension of building up from a flat surface, but I have to question the idea that Maya was the first to use the Z depth coordinate system. What about the software used in the 70s by Ed Catmull, who made the first ever computer generated animation? I'm sure it was using the screen space concept too.

I don't think I ever stated that Maya was the "first" to use it. What I did say, in my second post beneath Lobo's, was the up until Maya, most 3d software used the World Space (Z=Up) coordinate system.

What I actually meant, and should have said was, 3d _modeling _software, or CAD. Animation software has always used the screen-space coordinate concept, that's true. PowerAnimator was the software that would eventually become the Maya we know today. That was also released in 1990, around the time of 3dsmax for DOS, but unlike 3dsmax, it worked with the Unix/Irix operating system. It was primarily used for creating animation, so obviously it used the screen space coordinate system, because back then, almost all animation was 2d. Even earlier than that, Video Toaster was introduced at the World Of Commodore expo in 1987, and released as a commercial product in 1990 on the Amiga. Again, it was primarily for video animation editing. Pretty much any software that was geared toward animation would use the screen space coordinate system (Z=Depth), and that makes sense. However, CAD and 3d modeling still made more sense in the World Space coordinate system, and software was being released with the Z=UP coordinate system if their primary purpose was creating models or architecture that would be represented as real world objects.
Ton Roosendaal began rewriting the software that would become Blender in about 1995. So it seems he decided at this time to use the World Space coordinate system, for whatever reason. What I did suggest, and stand by,however, is that after about 1998, almost all 3D software that came out adopted the screen space concept of depth, and most continue in that vein even today.

I believe Sketchup uses the Z-up coordinate system too.

maxxxmodelz posted at 1:19PM Sun, 22 November 2015 - #4240265

I believe Sketchup uses the Z-up coordinate system too.

Yep, I think you're right. Considering Sketchup's purpose, I think it makes sense to have it that way too.

Interesting thread.