How many coordinate systems does MSFS need?

If I have counted correctly, there are at least three involved in aircraft creation and debugging:

Firstly, the 3D model. The SDK says “In the Z axis the center should be approximately where the water level would be”. Meaning that positive Z is upwards. Which matches what most people would call the Z axis, I guess. And positive X is to the left, positive Y is towards the back of the aircraft. A right-hand coordinate system. OK.

Then, when talking about the aircraft once inside the sim, the SDK says “longitudinal (z), where to the front is positive and to the back negative, lateral (x), where to the right is positive and to the left negative, vertical (y), where vertically up is positive and to the down is negative” OK. This now suddenly then a left-hand coordinate system, and all axes different from those in the 3D model. Fun (not). But I guess some deep legacy reasons. And I guess the idea is that different people work on the 3D model and the flight model anyway. (Haha, maybe at companies like Asobo or Aerosoft, but not the case for individual add-on developers.)

But that is not all. If you look in the “Debug Aircraft Weight” window from the Aircraft Editor, there suddenly is this text, applying to part of the values: “Negative is forwards! Offset backwards from Datum”. Ouch.

:wink: Polite , you …

Just do not get that upset … not yet.
In upcoming “updates” there could be more …
… coordinate systems , as you say.

Greetings

All I can say is that from previous professional experience, this is unfortunately not uncommon. Typical coordinate convention for those of us who work in simulation development is one thing, for graphics modeling it’s another.

Kind of damned if you do, damned if you don’t… if you consolidated coordinate just for MSFS you’d then have one group or another like “Well why is MSFS the only application that’s got to be non-standard with my work.”

Then in my line of work there’s variation in sign convention even with axes running the same directions, i.e. SAE vs. ISO…

Suffice to say it’s messy, and MSFS is not any different from anything else in that regard.

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