Orientation of z axis (Please don't laugh...)

[Anonymous]

When I orient to look from the top, why doesn't the z axis come towards me?

The y axis does instead. 

Have I broken it somehow? 

Can it be changed? 

Why is it like this?

I've come from 123d and it seemed logical that the x and y are flat on the ground with the z rising out of the ground.

[liujac]

Hi,

You may change it to z up on Preferences dialog.

Capture.PNG 

Regards,

Jack

[Anonymous]

Hey thanks. 

and can i get / set the y up / z up setting in the api?

[liujac · Accepted solution]

Yes, this option can be changed by API GeneralPreferences.defaultModelingOrientation.

import adsk.core, adsk.fusion, adsk.cam, traceback

def run(context):
    ui = None
    try:
        app = adsk.core.Application.get()
        ui  = app.userInterface
        app.preferences.generalPreferences.defaultModelingOrientation = adsk.core.DefaultModelingOrientations.ZUpModelingOrientation
        ui.messageBox('Hello script')

    except:
        if ui:
            ui.messageBox('Failed:\n{}'.format(traceback.format_exc()))

Jack

[Anonymous]

Thanks Jack

[wkveitsiti]

Nothing changes in the display when I change the Default modeling orientation to Z up in the General preferences.  X still point right, Y still points through the top, Z still points through the Front. Why is this so difficult?

[ekinsb]

Changing the preference setting just changes it for any new documents you create but doesn't do anything to existing documents.  To change the orientation for an existing document reorient the view to what you want as either the front or top and then in the view cube menu use the "Set current view as" option and choose "Front" or "Top" to reset the view orientation.

currentView.png

[Anonymous]

As for the WHY of this "strange default" - it's very historical. Here's the short short version as I recall it.

In the beginning there were only text terminals.

(0,0) referred to the first character in the first row on the display - which appeared in the top left. 

Next came 2D graphical interfaces and 2D games. These stuck with the convention everyone was used to that 0,0 is in the top left.

This history is why in most drawing API's X runs from left to right and Y runs from top to bottom.

Next came a revolution - faking 3D with perspective drawing in "real time" using really amazing programming tricks (all before the days of 3D acceleration).

As 3D graphics emerged X and Y were already well established in what i'll call screen space where 0, 0 was fixed at the top left. This meant that Z must therefore be in the direction of the user and the wall behind the screen. As an artist who only knows the old 2D system if you were to 'draw' a house in this new 3D which way would you consider to be "up"? Today nearly all physics engines, game engines, and 3D graphics engines treat the X,Z plane as "ground" and the Y axis as elevation - it can really be frustrating to get used to but if you can think about it as "from the screens perspective" it make sense as the user will view the virtual world mapped to this 2D display which treats X as left-right and Y as up-down.

[alodi2]

Now that I read your responce to the confusion of Y being up and down vs. Z, I have question as well. Why do most VMC machines in the world have Z as up. Ive always used Z as up because my machines just work better that way or it makes more sense to use the machines that way. Everything Ive learned so far from basic geometry to complicated programming is taught  with the X/Y table flat.  I am relatively new at Fusion 360 and so far the  video lessons have Y as up  which makes the work harder for me. Its  like driving an excavator with the switch turned the opposite way. I just don’t understand, and id like to stick to one way. In your opinion should I relearn Y as up to make communication  of the work easier with most of you guys and Fusion as well. Please note that my frustration is totally not with you, its because I’m breaking my neck learning this stuff and this subject really makes it harder for me, especially in the tutorials.

[Anonymous]

I model with z up, it just makes it easier to drop my parts into the slicer for 3d printing. I say do what is right for your toolchain, but I'm just a hobbyist 😉

[alodi2]

I totally agree!! Thank you

[BrianEkins]

I don't understand the reasoning for not having Z as up either.  I voiced my concern for this before Inventor was released but obviously it didn't matter and Fusion 360 has continued in the same way.  If you're just designing, I guess it doesn't really matter how front and top are oriented as long as it makes sense to you.  But if you're manufacturing the part then Z up is what's correct.  Since the software is intended for manufacturing it seems like that would be the logical default.  At least we can change it but it does mean a lot of the tutorials and videos still use the default.

[alodi2]

Thank you, that seems the sensible way to me as well. Thank you for the reply, I really appreciate it!