What is the "W" Channel

[Timothy]

I have noticed that in some of the tutorials I have watched, and also when I look down in one of the channel views I sometimes see a "W", as in "Transform.Rotate.W". What does that mean please?

[HomeSlice]

I'm think W is the forth axis for a Quaternian driver. I believe bones in AM use the Quaternian coordinate system when rotating because it prevents gimbal lock. But I don't really understand all of that.

[robcat2075]

Yes, W is a fourth component of the Quaternion rotation values. I have never read an explanation of them that matched up with what I was seeing.

 

you may sometimes read that Quaternions are bad because they are hard to edit, but the truth is most CG animators only have a fuzzy idea of what even X, Y and Z are about.

 

Quaternions do give vastly better interpolation for most character animation situations. Don't worry too much about the exact values, the real worth of the curve editor is seeing the slopes that go thru the keyframes.

 

Many times you can adjust an x y or z rotation and not bother with the W. If you do get an unexpected result, undo, then use the rotate manipulator to rotate the object on screen in the direction you wanted and observe the result in the graph.

 

I have no idea where Quaternia is.

[Luuk Steitner]

Quaternions are a bit complex to understand but if you like to know all about it, visit this page: http://en.wikipedia.org/wiki/Quaternion

If you want direct access to X, Y and Z values in the graph time line it can sometimes be easier to change the rotation driver to euler.