Spinning a globe.

Here’s the issue I am running into. I am trying to animate a sphere rotating using key frames. My problem is that I am getting a wobble. Is there some way I can lock the Z axis to prevent this? If not, is there another option besides turning every frame into a key frame? Thanks.

  • Floyd

Hi
You should have a look into IPO Editing.
http://wiki.blender.org/index.php/Manual/Ipo_Curves_and_Keyframes
You just need two Keyframes for one complete 360 degrees rotation,
And after editing them for your needs you can extrapolate them in the IPOEditor.
You can lock your movement to the z axis, by just setting keys on ROTZ.

Pat

Looks like what I need to do is figure out how to use the local z axis to rotate. I either need to get it in local mode or just add an ipo curve for locz. Thanks for the reply.

  • Floyd

Still get the wobble. The issue is the sphere is not aligned with the global axis. When I try to us the rotation from the ipo, it uses global and I get the wobble. If I rotate it locally, it looks fine, till I animate it. Then I get the wobble.

  • Floyd

To rotate around a local axis, just press “z” twice…(Or whichever axis you’re rotating around…)

Hopefully this works, other wise I have no clue…

The simplest way to use the Z local axis is to parent your globe to an object.
This object can be the default cube, an Empty or any other object.
If you have added an UV sphere in top view, the local axis of your globe is Z.
Folow these steps :

  • Insert a Rot keyframe at frame 1.
  • Go to frame N.
  • Type R Z Z (As you sphere has been added in top view, you can type R Z as well, because the Local axis and the global axis are the same) and insert a new Rot keyframe.
  • In the Ipo object panel, select all your curves and type T.
  • Select Linear.
  • Set the Curve to Extend Mode: Extrapolation.
  • Now, give the wanted slope to the object used as parent (cube, empty…)
    Your globe will rotate perfectly on its own Z axis for ever with the needed angle.

Thanks for the replies. I figured it out last night but I’m not sure how. I did have the globe track an empty axis which moved to eight points on a circle. I plan to post it as soon as I can, although Mountain Conn is this weekend so I’ll probably have to wait till next week. I’ll be running an panel there and showing it along with other renders I’ve complete over the years.

  • Floyd

When you use local coordinate for animation, you must know that local coordinates are different from Global coordinates only if the animated object has a parent ! Local coordinates are relative to the parent object, so using them without a parent object will give exactly the same behaviour as global coordinates !

This is not that confusing, if you understand how empties work. Here’s the process I’ve used:

• Set the angle of the globe to 0 (set it pointing straight up). Add an empty, and parent the globe to the empty.

• Rotate the empty to the desired angle. The globe will rotate with it.

• Select the globe (not the empty) and open the Transform Properties window by pressing [n]. You may now adjust the “RotZ” value however you like, and the globe will rotate on the local z axis. For example, key frame #1 with the value at zero, then key frame #100 with the value at 360.

• As ROUBAL pointed out, to get a constant spin, you’ll need to select the IPO curve for RotZ, press [t] and select “Linear.” To get a non-stop spin, press [e] and select “Extrapolation.”