two linked 'Child of - constraint' causes object to jump at 180 degree rotation #40671

New Issue

Henri Seppänen · 2014-06-17T14:05:08+02:00

Henri Seppänen commented

2014-06-17 14:05:08 +02:00

System Information
Ubuntu 14.04

Blender Version
Broken: 2.71 RC, 169c95b

Short description of error
If at least three objects are linked by two child of constraints, where the second constraint influence is set to 0.5 (not 1) the third object jump after 180 degree rotation

Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps

Create three cubes on the x axis.
set first cube to rotate 360 degree
attach child of - constraint to second cube. Target first cube. Set influence to 0.5
attach child of - constraint to third cube. Target second cube. Influence 1.0

You will see that the third cube jump when the first cube has rotated 180 degrees. The problem is that the second cube orient itself at 180 degrees.

Speculation
The cause of the reason might be how the rotation vector has been defined, that it needs to make 720 degree turn to get back to original position. This might be missed in Child of - constraint.

This is my first bug report. I would like to receive any feedback to learn to report bugs better next time.rotation_bug_report.blend

**System Information** Ubuntu 14.04 **Blender Version** Broken: 2.71 RC, 169c95b **Short description of error** If at least three objects are linked by two child of constraints, where the second constraint influence is set to 0.5 (not 1) the third object jump after 180 degree rotation **Exact steps for others to reproduce the error** Based on a (as simple as possible) attached .blend file with minimum amount of steps 1) Create three cubes on the x axis. 2) set first cube to rotate 360 degree 3) attach child of - constraint to second cube. Target first cube. Set influence to 0.5 4) attach child of - constraint to third cube. Target second cube. Influence 1.0 You will see that the third cube jump when the first cube has rotated 180 degrees. The problem is that the second cube orient itself at 180 degrees. **Speculation** The cause of the reason might be how the rotation vector has been defined, that it needs to make 720 degree turn to get back to original position. This might be missed in Child of - constraint. ------------------------------ This is my first bug report. I would like to receive any feedback to learn to report bugs better next time.[rotation_bug_report.blend](https://archive.blender.org/developer/F94530/rotation_bug_report.blend)

Henri Seppänen commented

2014-06-17 14:05:08 +02:00

Changed status to: 'Open'

Henri Seppänen self-assigned this 2014-06-17 14:05:08 +02:00

Henri Seppänen commented

2014-06-17 14:05:08 +02:00

Added subscriber: @hoseppan

Joshua Leung commented

2014-06-17 15:21:36 +02:00

Changed status from 'Open' to: 'Archived'

Joshua Leung closed this issue

2014-06-17 15:21:36 +02:00

Joshua Leung commented

2014-06-17 15:21:36 +02:00

Added subscriber: @JoshuaLeung

Joshua Leung commented

2014-06-17 15:21:36 +02:00

This is another one of those intractable issues related to matrix decomposition limitations causing issues when trying to blend between the results of different constraints, not to mention the fact that the childof constraint needs to do some fairly evil space-conversion things which don't really play nicely when applied partially.

Closing as a "won't/can't fix" and noted in wiki.

This is another one of those intractable issues related to matrix decomposition limitations causing issues when trying to blend between the results of different constraints, not to mention the fact that the childof constraint needs to do some fairly evil space-conversion things which don't really play nicely when applied partially. Closing as a "won't/can't fix" and noted in wiki.

Henri Seppänen was unassigned by Joshua Leung

2014-06-17 15:22:09 +02:00

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

two linked 'Child of - constraint' causes object to jump at 180 degree rotation #40671