Hi fellas I have a problem with solving an issue possible to find in the .blend file provided.

If You open the file there is a simple scene with constraints applied to the AXIS parenting two objects. Rotating the "toroid" along the Y GLOBAL rotates the axis along Z LOCAL. Problem is that to work as designed all objects has to be rotated simultaneously cause parenting axis to the toroid somehow break the global-local thing so to keep the axis in place all objects has to be rotated.

To test the function simply select ALL objects from the front view and rotate along Y so You could see how its working. Problem is when the rotation is finished, the next rotation does not work (global rotation somehow "resets" to 0,0,0 again imo and whole thing break-up).

Rotate for example for 30 degrees along Y, confirm it and try to rotate again to see what Im talking about. I need to solve this somehow but failed using all combinations in mind. Probably something else than constraints will be needed but dunno what.

Appreciate any idea and solutions buddies!

Sincerely, Jan

  • $\begingroup$ It seems to me that one problem is that you don't have the local Y axis of the empty, axle, or wing pointing in the direction you want, which I assume is along the major axis of the axle. Would changing that help? I also think you might want a copy rotation constraint on the empty with the toroid as target with only the Y axis copied world -> local. $\endgroup$ – Marty Fouts Nov 21 '18 at 22:45
  • $\begingroup$ Hi could You "repair" my file and re-send? In fact I dont really understand that "axis axle major pointing along" thing ;). $\endgroup$ – Jan Matys Nov 22 '18 at 0:03
  • $\begingroup$ I don't have an alternative that works yet, but I have tried to clarify my comment below. $\endgroup$ – Marty Fouts Nov 23 '18 at 20:59

Attempt to clarify what I wrote:

'Axle' is my short name for BezierCircle.004. You can display it's local axis by selecting it, going to the Properties window, Object tab, and enabling Display->Axis. (Here I have moved display to the top of the tab. It will normally be farther down)How to display object local axis

You will see that the local axis are parallel to the world axis. Now do the same for the empty. You will see that the empty's local axis are not the same. The Z axis of the empty points roughly in the direction that I meant by 'axis of axle'. (Here I've move the empty and the axle into local space. The yellow axis are that of the axle, orange that of the empty.Local axis of the empty and the object.

Now rotate all of the objects on the world Y axis. The local axes still have the same orientation with respect to their objects, so the next time you rotate the rotation will cause the effect that looks like a reset. Blend file with my version, which might not match your need:

Notice the axis orientation. The 'axle' and 'wing' have the same orientation as the empty. The Empty is the parent of the axle. The axle is the parent of the wing. There are two constraints on the empty: Copy (Y) Rotation and Limit Rotation.

It should be possible to arrange all of this so that only the rim has to be selected, but I didn't manage that.

  • $\begingroup$ In fact in Your 2nd image the orange is local of an object which I dont need and the red is the added axis of the rotation I need (respect the longitude of the object, not globals). Btw ... is there a way to set the rotation of the local axis of an object, ie rotate the orange like the red one? And yep, what I need is to rotate all the objects everytime like for the 1st time in my .blend file. $\endgroup$ – Jan Matys Nov 24 '18 at 0:21
  • $\begingroup$ Test Yo file and it works "somehow" no matter I need the rotation inverted but its only a matter of check-flag (done). The problem now is that the influence could be 1.0 MAX and I need about 1.2 Marty. Also the axis of the spoiler should point straight up (Z-up) but that takes us back to my previous question - how U rotate all those object locals? $\endgroup$ – Jan Matys Nov 24 '18 at 0:34

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