# Quaternion Child / Parent question

This topic is 2427 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

## Recommended Posts

I have a question regarding hierarchy and quaternions:

Usualy, when you have a child joint matrix and a parent matrix, the "child world matrix" = "child local matrix" * "parent world matrix".
So far, so good. The problem rises here:

If I compute my local matrix like this: rotation from quaternion to matrix and then apply the translation AND then multiply it with a parent rotation, don't I run again in the danger of gimbal lock?

The situation:
1.) local = rotation matrix from quaternion
3.) world matrix = "local matrix" * "parent.world matrix"- isn't that dangerous? Gimbal lock?

Feel free to post.

##### Share on other sites
I was also wondering:

a) Can gimbal lock ONLY appear when you compose a rotation matrix
b) can gimbal lock appear when you multiply two allready computed rotation matrices (child by parent) ?

##### Share on other sites
Gimbal lock means that you have several orthogonal roations happening in some order, and one rotation is of a kind so your coordinate system (or originally the gimbal) appears to "lose" a subsequent axis of rotation, for example by rotating the x onto the y axis. This is problematic for Euler angles, because they do just that, rotate around one axis at a time.

Unit quaternions (and matrix rotations) are equivalent to rotation around an arbitrary vector that you specify directly (in one step), so there is no such problem per se, in one rotation. But of course it is in general possible to generate something like gimbal lock with 2 or 3 subsequent rotations, too. But there's not much you can do about that, really. Nor do I think it's a problem, that's just a property of orthogonal rotations in 3D space.

1. 1
2. 2
Rutin
13
3. 3
4. 4
5. 5

• 9
• 9
• 14
• 12
• 10
• ### Forum Statistics

• Total Topics
633262
• Total Posts
3011128
• ### Who's Online (See full list)

There are no registered users currently online

×