Ball Joint is missing a DOF and has redundant DOF's

[Noah_Katz]

As seen in the video, there seems the pitch and roll are both about the global X axis, yaw is about the Z axis, and rotation about the Y axis is missing.

.f3d is attached

[jhackney1972]

The reason you are seeing this behavior is because you used two edges to create the Ball Joint.  The edge causes the axis, you are questioning, to stay aligned.  Compare to the model attached where two points are joined with a Ball Joint.

[jeff_strater · Accepted solution]

I think you might be referring to a topic that has come up before:

• ball-joint-mysteries 
• spherical-joint-and-golden-hind 
• scratching-the-ball 

[Noah_Katz]

I still only get two DOF, and I modified your model join to one point to the another point and same thing - pitch and roll give the same motion.

I wasn't aware that Fusion tried to figure out your intention from the geometric features being joining.

Is this documented somewhere?

When I originally read up on joints (years ago) I didn't see any mention of this.

[Noah_Katz]

Thanks for the links, I'll take a look at them a bit later.

[Noah_Katz]

The links were very helpful, thanks, Jeff.

And I also didn't know that you could double click on the joint flags, what a time-saver!

> if you are frustrated by the Z's being aligned (gimbal lock), unalign them by changing the X' angle to be other than 0 or 180 degrees

Would it be possible to have defaults set to be other than those two angles?

Also, presuming it hasn't already been, I suggest adding a note to the online instructions to see these links if trouble is encountered.