Hey ya’ll, I’ve found a major bug with the gizmos + rotation quaternion, after spending plenty of hours debugging :upside_down_face:. I’ve created a PG: https://playground.babylonjs.com/#31M2AP#159 Simply drag the position gizmo back-n-forth, and the world matrix determinant keeps getting smaller…

I can confirm that this bug exists in alpha.3 as well (and apparently all the way back to 4.2)

Typical issue with unnormalized quaternion. Fixed here in this PG: MASSIVE BUG: GIZMO + SCALE | Babylon.js Playground I’ll do a PR to automate that.

Thanks Cedric! Does this mean each time we would have to normalize all nodes that use .rotationQuaternion in the render loop? Or would the PR address this by forcing normalization in the node class itself?

the second. I’ll normalize the quaternion (if any) for nodes that are modified by a gizmo.

Cool! Is this because the gizmos are affecting the quaternion (also why is positionGizmo affecting the quaternion xD)? Or is this more fundamental i.e. should be adjusted each cycle regardless if it’s from gizmo or not Interested to learn the internals :slight_smile:

gizmos work mostly with matrices and matrix is decomposed into translation/rotation and scale once done. After a while, the conversion between matrix and quaternion drifts a little and you have to normalize it.

PR is live Normalize quat/update matrix for drag behavior by CedricGuillemet · Pull Request #9968 · BabylonJS/Babylon.js · GitHub

MASSIVE BUG: gizmo + rotationquaternion

Bugs

mrlooi February 25, 2021, 2:41pm 10

gotcha

IE11 navigator.getGamepads - Babylonjs no longer working in IE11

Topic		Replies	Views
Rotation Gizmo with previous quaternion set in code Bugs	5	1076	July 3, 2019
[Gizmo] - Wrong rotation after usage of position gizmo Bugs engine , gizmo	17	646	December 5, 2023
Inspector rotation quaterning bugging out Bugs	8	1498	April 17, 2019
Rotation Gizmo does not Update Quaternion Questions	6	158	April 12, 2024
Rotation Gizmo on meshes with parents Questions	13	1682	May 7, 2019

MASSIVE BUG: gizmo + rotationquaternion

Related topics