Joint axes are wrong when using Y-axis up setting

[hoegge]

When you use the Y-up setting the axis settings in joints are wrong. They behave as you are still using Z-up. Seems like the joint tools do not know about and correct for this setting.

 

[jeff_strater]

Joint axes/coordinate system have no relation to either component or global axes/coordinate system.  They are purely local coordinate systems that depends on the geometry selected for the joint origins.  If you pick a planar face, the joint origin coordinate system will be set with its Z axis along that plane's normal.

[hoegge · Accepted solution]

So they are the imaginary "axes" of the target component face "disc" you select. Makes sense (of course 🙂 ), since this coordinate system is rarely aligned with the global coordinate system). The "joint" coordinate system does not, though, respect the Y-up setting and always have Z-up then. Might be smart to annotate the blue arrows with X, Y and Z.

Thanks for quick answer @jeff_strater 

[jeff_strater]

@hoegge - you are correct, and you raise a good point.  Calling these things X, Y, and Z is misleading.  I've wondered for a while whether we should change these to U, V, W or something...

[hoegge]

@jeff_strater Yes - that would make a lot of sense, or i, j, k (also often used in geometry) - and important - add then to the 3 shown local axis lines on the object, so you can easily see what is what