Maniphest T41950

Parent-Child Menu behaves weird
Closed, Resolved
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Assigned To
Bastien Montagne (mont29)
Authored By
Sebastian Koenig (sebastian_k)
Sep 25 2014, 12:33 PM
Tags
  • BF Blender
Subscribers
Bastien Montagne (mont29)
Campbell Barton (campbellbarton)
Sebastian Koenig (sebastian_k)

Description

System Information
OSX 10.9.5, GTX 660ti

Blender Version
Broken: 2.72 RC
Worked: pretty sure this is broken forever, i remember seeing weird behavior here before

Short description of error
Assigning object B as parent to an object A via the parent field in object relations panel in properties editor behaves differently depending on if object A has been a child before or not. For a user it is totally unclear what happens.

Exact steps for others to reproduce the error
Open the attached file

parent_child_bug.blend499 KBDownload

Use the eyedropper tool or the text field to assign the object "parent" as parent to "ex-child" via the relations panel on the right side of the screen. The object stays in place.
Do the same with the object "new_child" and see how it uses the scale factors of the parent.
The only difference between the 2 objects is that i had parented "ex_child" to "parent" before through ctrl+p and cleared the parent after that by pressing the X in the parent selection field in the relations panel.

Revisions and Commits

rB Blender
rB0763771e9466 Fix T41950: Parent-Child Menu behaves weird
rBb100bdca25b1 Fix T41950: Parent-Child Menu behaves weird

Related Objects

Event Timeline

Sebastian Koenig (sebastian_k) created this task.Sep 25 2014, 12:33 PM
Sebastian Koenig (sebastian_k) assigned this task to Campbell Barton (campbellbarton).
Sebastian Koenig (sebastian_k) raised the priority of this task from to 90.
Sebastian Koenig (sebastian_k) updated the task description.
Sebastian Koenig (sebastian_k) added a project: BF Blender.
Sebastian Koenig (sebastian_k) edited a custom field.
Sebastian Koenig (sebastian_k) added a subscriber: Sebastian Koenig (sebastian_k).
Bastien Montagne (mont29) added a subscriber: Bastien Montagne (mont29).Sep 25 2014, 12:57 PM

When you parent with ctrl-P, you are calling an operator which performs additional computation (namely, setting the inverse parent matrix), which allows child to keep its current transform. When you use the ID selector, you only affect the 'parent' property of the object, without touching any other data, like its inverse parent matrix…

No bug here, but agree from user POV this is not much understandable, so maybe we should make this field non-editable… But then, would not be much useful either. :/

Bastien Montagne (mont29) lowered the priority of this task from 90 to Normal.Sep 25 2014, 12:58 PM
Sebastian Koenig (sebastian_k) added a comment.Sep 25 2014, 1:02 PM

Thanks for explaining.
I was suspecting something like that, but maybe this could be somehow exposed to the user? With some has-inverse-matrix info thingy or so? Because as it is now it's really totally obscure...
Maybe add to design to-dos and close this.

Bastien Montagne (mont29) claimed this task.Oct 10 2014, 6:47 PM
Bastien Montagne (mont29) added a subscriber: Campbell Barton (campbellbarton).

Will just make it so that inverse parent matrix is reset every time you clear parenting ;)

Bastien Montagne (mont29) changed the task status from Unknown Status to Resolved.Oct 10 2014, 6:48 PM
Bastien Montagne (mont29) added a commit: rBb100bdca25b1: Fix T41950: Parent-Child Menu behaves weird.

Closed by commit rBb100bdca25b1.

Sergey Sharybin (sergey) added a commit: rB0763771e9466: Fix T41950: Parent-Child Menu behaves weird.Oct 15 2014, 1:08 PM
Campbell Barton (campbellbarton) mentioned this in BF Blender: Regressions.Oct 15 2014, 5:17 PM
Sybren A. Stüvel (sybren) mentioned this in T80490: Child Object jumps away with changing the parent bone.Sep 8 2020, 10:36 AM