Drivers: duplication won't preserve targeted objects #39079

New Issue

Mikhail Rachinskiy · 2014-03-10T04:50:42+01:00

Mikhail Rachinskiy commented

2014-03-10 04:50:42 +01:00

System Information
Windows 8.1 x64
Renderer: GeForce GTX 650/PCIe/SSE2
Vendor: NVIDIA Corporation
Version: 4.4.0

Blender Version
Broken: 2.69.8 36279af

Short description of error
Targeted objects are not preserved when duplicate with single driver.

Exact steps for others to reproduce the error

Open blend file driver.blend
Select 1st object (3 drivers rotation) and duplicate it = driver targets are preserved
Select 2nd object (1 driver location) and duplicate it = driver targets are not preserved
Select last object and duplicate it = driver targets are not preserved

Here is the image of which targets I am talking about

**System Information** Windows 8.1 x64 Renderer: GeForce GTX 650/PCIe/SSE2 Vendor: NVIDIA Corporation Version: 4.4.0 **Blender Version** Broken: 2.69.8 36279af **Short description of error** Targeted objects are not preserved when duplicate with single driver. **Exact steps for others to reproduce the error** - Open blend file [driver.blend](https://archive.blender.org/developer/F80500/driver.blend) - Select 1st object (3 drivers rotation) and duplicate it = driver targets are preserved - Select 2nd object (1 driver location) and duplicate it = driver targets are not preserved - Select last object and duplicate it = driver targets are not preserved Here is the image of which targets I am talking about ![drivers.png](https://archive.blender.org/developer/F80501/drivers.png)

Mikhail Rachinskiy commented

2014-03-10 04:50:42 +01:00

Changed status to: 'Open'

Mikhail Rachinskiy commented

2014-03-10 04:50:42 +01:00

Added subscriber: @MikhailRachinskiy

Lukas Tönne commented

2014-03-10 09:44:58 +01:00

Added subscriber: @LukasTonne

Lukas Tönne commented

2014-03-10 09:44:58 +01:00

What happens here is an automatic re-targetting of ID block references on duplicating:

Any pointer inside duplicated objects, which points to one of the duplicated objects, is set to the respective new object copy.

For a single object this means that only references from this object to itself are re-targetted.

The first object's drivers use the object itself -> gets re-targeted
The second object's driver uses a different object which is not duplicated along with it -> no re-targeting
The third object's driver uses a different object -> no re-targeting. The Shape Keys are actually a separate datablock which IIRC is not duplicated along with the object, so even if it referenced the same object that link may get lost / end up wrong.

It's not ideal, but can't think of an unambiguous way to do it better ...

What happens here is an automatic re-targetting of ID block references on duplicating: *Any pointer inside duplicated objects, which points to one of the duplicated objects, is set to the respective new object copy.* For a single object this means that only references *from* this object to *itself* are re-targetted. * The first object's drivers use the object itself -> gets re-targeted * The second object's driver uses *a different object* which is not duplicated along with it -> no re-targeting * The third object's driver uses a different object -> no re-targeting. The Shape Keys are actually a separate datablock which IIRC is not duplicated along with the object, so even if it referenced the same object that link may get lost / end up wrong. It's not ideal, but can't think of an unambiguous way to do it better ...

Mikhail Rachinskiy commented

2014-03-10 11:04:35 +01:00

Sorry I messed up with the example, yes the issue is appearing only with shapekeys.

Well this is a very serious flaw, with current system it is not possible to make simple animations with many objects in relation to the distance between empty and the object itself, like this:

Sorry I messed up with the example, yes the issue is appearing only with shapekeys. Well this is a very serious flaw, with current system it is not possible to make simple animations with many objects in relation to the distance between empty and the object itself, like this: ![mg4-3.gif](https://archive.blender.org/developer/F80517/mg4-3.gif)

Bastien Montagne commented

2014-03-18 15:57:22 +01:00

Added subscriber: @mont29

Sergey Sharybin commented

2014-04-10 18:49:49 +02:00

Added subscriber: @Sergey

Sergey Sharybin commented

2014-04-10 18:49:49 +02:00

@LukasTonne, is it something solvable with current design or it's a limitation of it a rather a TODO?

Lukas Tönne commented

2014-05-03 08:59:33 +02:00

I think this is not strictly speaking a bug. We could consider extending the duplication such that:

Any Object pointer referenced by a duplicated Object or a nested data block (i.e. shape keys) is redirected

However, this leads us into ambiguous territory. By their nature, data blocks such as shape keys can be shared among many different objects. Redirecting driver targets when any of these is duplicated might work in one case but have undesired results in others. It might be difficult to prevent circular references and such.

I would prefer to leave the system as it is now, only modify Object pointers directly inside Object data blocks.

@MikhailRachinskiy: For the use case you describe, where a great number of objects need to be set up with correct drivers, it's preferable to write a specialized tool (i.e. a python script). The generic duplicate operator simply is not capable of guessing the desired outcome correctly.

I think this is not strictly speaking a bug. We could consider extending the duplication such that: *Any Object pointer referenced by a duplicated Object **or a nested data block** (i.e. shape keys) is redirected* However, this leads us into ambiguous territory. By their nature, data blocks such as shape keys can be shared among many different objects. Redirecting driver targets when *any* of these is duplicated might work in one case but have undesired results in others. It might be difficult to prevent circular references and such. I would prefer to leave the system as it is now, only modify Object pointers directly inside Object data blocks. @MikhailRachinskiy: For the use case you describe, where a great number of objects need to be set up with correct drivers, it's preferable to write a specialized tool (i.e. a python script). The generic duplicate operator simply is not capable of guessing the desired outcome correctly.

Mikhail Rachinskiy commented

2014-05-03 18:41:38 +02:00

@LukasTonne or implement a new object target selectors such as:
This object - pointing at current object, similar to jQuery $(this)
Parent object - pointing at parent object from current object, similar to jQuery $(this).parent()

Of course This object selector would not be possible for all modifiers or constraints, and it is no way to be implemented in the near future (or implemented at all). Just my thoughts on how selector system could be augmented, if you have intentions about it.

@LukasTonne or implement a new object target selectors such as: **This object** - pointing at current object, similar to jQuery **$(this)** **Parent object** - pointing at parent object from current object, similar to jQuery **$(this).parent()** ![Untitled.png](https://archive.blender.org/developer/F86798/Untitled.png) Of course **This object** selector would not be possible for all modifiers or constraints, and it is no way to be implemented in the near future (or implemented at all). Just my thoughts on how selector system could be augmented, if you have intentions about it.

Sergey Sharybin commented

2014-05-19 17:27:33 +02:00

Changed status from 'Open' to: 'Archived'

Sergey Sharybin closed this issue

2014-05-19 17:27:33 +02:00

Sergey Sharybin self-assigned this 2014-05-19 17:27:33 +02:00

Sergey Sharybin commented

2014-05-19 17:27:33 +02:00

Agree with Lukas. Moving to TODO http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Animation#Animation_System

Thanks for the report, but closing it now.

Agree with Lukas. Moving to TODO http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Animation#Animation_System Thanks for the report, but closing it now.

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Drivers: duplication won't preserve targeted objects #39079