Link duplicated & shift parented object displays wrong transform #68190

New Issue

Robert S · 2019-08-03T20:54:37+02:00

Robert S commented

2019-08-03 20:54:37 +02:00

System Information
Operating system: Windows 10 1903
Graphics card: 1080ti

Blender Version
Broken: 2.80 release

Short description of error

Exact steps for others to reproduce the error

Link duplicate the object named LINK-DUPLICATE-THIS
Shift drag that object into EmptyB
Go to the transform tab and type 0 in all location coordinates

Result:

The object is placed at the world zero (even though the relationship line is correct).

Expected result:

The object should be placed a the parent zero.

ParentTransformBug.blend

**System Information** Operating system: Windows 10 1903 Graphics card: 1080ti **Blender Version** Broken: 2.80 release **Short description of error** ![Untitled-1.png](https://archive.blender.org/developer/F7647521/Untitled-1.png) **Exact steps for others to reproduce the error** 1. Link duplicate the object named LINK-DUPLICATE-THIS 2. Shift drag that object into EmptyB 3. Go to the transform tab and type 0 in all location coordinates Result: * The object is placed at the world zero (even though the relationship line is correct). Expected result: * The object should be placed a the parent zero. [ParentTransformBug.blend](https://archive.blender.org/developer/F7647525/ParentTransformBug.blend)

Robert S commented

2019-08-03 20:54:37 +02:00

Added subscriber: @RobertS

tom k commented

2019-08-04 14:49:02 +02:00

Added subscriber: @tomjk

tom k commented

2019-08-04 14:49:02 +02:00

I think this is correct behaviour. I'm guessing that internally blender does this: first unparent the object from the old parent, then parent it to the new parent. That is the equivalent of this:

Object Menu -> Parent -> Clear Parent (or Alt-P -> Clear Parent)
Shift-select EmptyB
Object -> Parent -> Object (or Ctrl-P -> Object)

Clearing the parent puts the object back at world origin, which is correct.
Setting new parent fills in the Parent Inverse Matrix so that the object stays in the same place relative to the world (so, still world origin).

the Parent Inverse Matrix is a feature of Blender to prevent your carefully placed objects from going somewhere else after you parent them. In this case it is fighting against you.

What you want to do after parenting to EmptyB, then, is select your newly-childed object and press Object -> Parent -> Clear Parent Inverse (or Alt-P -> Clear Parent Inverse). Now, location [0,0,0] puts your object at the Parent origin for reals.

I *think* this is correct behaviour. I'm guessing that internally blender does this: first unparent the object from the old parent, then parent it to the new parent. That is the equivalent of this: 1. Object Menu -> Parent -> Clear Parent (or Alt-P -> Clear Parent) 2. Shift-select EmptyB 3. Object -> Parent -> Object (or Ctrl-P -> Object) Clearing the parent puts the object back at world origin, which is correct. Setting new parent fills in the Parent Inverse Matrix so that the object stays in the same place relative to the world (so, still world origin). the [Parent Inverse Matrix ](https://docs.blender.org/manual/en/2.80/scene_layout/object/properties/relations/parents.html#parent-inverse) is a feature of Blender to prevent your carefully placed objects from going somewhere else after you parent them. In this case it is fighting against you. What you want to do after parenting to EmptyB, then, is **select your newly-childed object and press Object -> Parent -> Clear Parent Inverse** (or Alt-P -> Clear Parent Inverse). Now, location [0,0,0] puts your object at the Parent origin for reals.

Robert S commented

2019-11-05 22:15:00 +01:00

@tomjk I'm sorry, but you may very well be correct, but I still do not understand your "correct" explanation.

Just like I don't understand how this picture from 2.81 can in any way be "correct":

Left is a curve where I've even made sure to snap the origin to the first CV via the 3D cursor
Mid is the actual document origin
Right is a camera parented to the curve with zeroed out coordinates, and yet it's at a seemingly random location

This transform behavior in Blender makes no sense to a new user (and even a user who is used to animating in 3D Studio Max and Unreal, like I am).

@tomjk I'm sorry, but you may very well be correct, but I still do not understand your "correct" explanation. Just like I don't understand how this picture from 2.81 can in any way be "correct": ![bild.png](https://archive.blender.org/developer/F7952263/bild.png) - Left is a curve where I've even made sure to snap the origin to the first CV via the 3D cursor - Mid is the actual document origin - Right is a camera parented to the curve with zeroed out coordinates, and yet it's at a seemingly random location This transform behavior in Blender makes no sense to a new user (and even a user who is used to animating in 3D Studio Max and Unreal, like I am).

Germano Cavalcante commented

2019-11-07 20:08:19 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2019-11-07 20:08:19 +01:00

Changed status from 'Open' to: 'Archived'

Germano Cavalcante closed this issue

2019-11-07 20:08:19 +01:00

Germano Cavalcante self-assigned this 2019-11-07 20:08:19 +01:00

Germano Cavalcante commented

2019-11-07 20:08:19 +01:00

This is not a bug, the confusion is because the parent inverse matrix is hidden (ie not displayed in the interface).
The user should be aware of what kind of parenting is done in each situation.

This seems like it belongs in the paper cut thread and not the bug tracker:
https://devtalk.blender.org/c/user-feedback/paper-cuts

For suggestions on how to improve the UI, please use other channels:
https://wiki.blender.org/wiki/Communication/Contact#User_Feedback_and_Requests

This is not a bug, the confusion is because the parent inverse matrix is hidden (ie not displayed in the interface). The user should be aware of what kind of parenting is done in each situation. This seems like it belongs in the paper cut thread and not the bug tracker: https://devtalk.blender.org/c/user-feedback/paper-cuts For suggestions on how to improve the UI, please use other channels: https://wiki.blender.org/wiki/Communication/Contact#User_Feedback_and_Requests

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Link duplicated & shift parented object displays wrong transform #68190