Why you changed from Quaternion WXYZ to XYZ Euler

[João Pedro Gaelzer]

I think these are one of the things that I need to understand well, and that has given me a little headache for not knowing exactly how it works.

[gimmi45]

Great question, i hope he answers 🙂

[spikeyxxx]

Simply put: if you have a simple rotation (for instance something only rotates around one axis), then you’d use Euler.

When you have complicated rotations , use quaternions. 

Suppose you use XYZ Euler and rotate an Object  +/- 90°, then you have what is called Gimbal lock; rotating around the X-axis:

is the ‘same’ (direction may be opposite) as rotating around the Z-axis:

When you have a rotation R1 followed by a rotation R2, then the total rotation is quite hard to figure out with Euler, with quaternions its a piece of cake 😉 (You just multiply the quaternion representation of R1 by the one of R2…again: simply put)

[João Pedro Gaelzer]

Thank you very much! I “googleled”  Gimble Lock and I found a video on YouTube, from Level Pixel Level, with examples about the this issue: https://www.youtube.com/watch?v=mCZItVfEtRY 

I got it! I think understood your explanation now. But how can I use the ‘W’? How can I avoid the Gimble rotation with the WXYZ? Again, thank you very much!

[spikeyxxx]

You will need to learn about quaternions. May I humbly suggest: https://blog.cgcookie.com/what-are-quaternion-rotations-in-blender/

Feel free to ask if something is still unclear after that. (It probably will be…)

[João Pedro Gaelzer]

Great! Thank you very much!

[Wayne Dixon]

Hi JP,

Yeah if you have any Quaternion questions throw them Spikey’s way.

But here is a general run down on when to use what….(but this is personal preference)

-If a control only needs to move on 1 axis -it is much easier to use Euler.

-If a control rotates on all 3 axes, Quaterion is a better option.  *however* sometimes it is easier to use Euler and deal with any gimbal lock on the spots where you encounter it (if at all)

And sometimes I am told to supply a rig in Euler XYZ by default.  (in Blender you can change the rotation mode and even keyframe this, so it’s not that big of a deal).  Although with this it best to use the same rotation mode for the entire shot.

I hope this helped and didn’t make more questions for you haha

[João Pedro Gaelzer]

I got it !! Thanks @waylow ! 🤣🤣🤣 This is a good – and easy – to remember:

-If a control only needs to move on 1 axis -it is much easier to use Euler.

-If a control rotates on all 3 axes, Quaterion is a better option. * however * sometimes it is easier to use Euler and deal with any gimbal lock on the spots where you encounter it (if at all)

Makes all the sense to me! I am beggining with 3D animation, so this is a good starting point for me in this subject. I know I will have issues on the way, but now I know where I can found the answers. I won´t be stucked. Thanks again!

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