2.79 -> 2.8 Maintain Volume constraint unexpected behaviour. #57376

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Predrag Lazic · 2018-10-25T00:57:24+02:00

Predrag Lazic commented

2018-10-25 00:57:24 +02:00

System Information
Linux version 4.9.13-1-MANJARO (gcc version 6.3.1 20170109 (GCC) x86_64 GNU/Linux
4 x Intel(R) Core(TM) i5-2400S CPU @ 2.50GHz
amd Radeon hd 6750M

Blender Version
2.79 - f4dc9f9d68
2.8 - 13cfb641c6

Short description of error
Primary Issue:
Linking proxy Rig does not handle scale of bones the same as in 2.79

Secondary Issue:
Updating the original file (such as changing bone rotation locks) doesn't transfer over to proxy file.

Exact steps for others to reproduce the error
Attached File.
In 2.8:
New File
File Link, select file, select collection, pick only group
Object - Relations - make proxy - newtonPendulum
In pose mode scale does not work on sphere rotary bones unless axis is specifically pressed (it does in 2.79). Scale behaviour is different from 2.79 rig also.
blender_2018.10.24_Newton(01).blend

System Information Linux version 4.9.13-1-MANJARO (gcc version 6.3.1 20170109 (GCC) x86_64 GNU/Linux 4 x Intel(R) Core(TM) i5-2400S CPU @ 2.50GHz amd Radeon hd 6750M Blender Version 2.79 - f4dc9f9d68b 2.8 - 13cfb641c6d Short description of error Primary Issue: Linking proxy Rig does not handle scale of bones the same as in 2.79 Secondary Issue: Updating the original file (such as changing bone rotation locks) doesn't transfer over to proxy file. Exact steps for others to reproduce the error Attached File. In 2.8: New File File Link, select file, select collection, pick only group Object - Relations - make proxy - newtonPendulum In pose mode scale does not work on sphere rotary bones unless axis is specifically pressed (it does in 2.79). Scale behaviour is different from 2.79 rig also. [blender_2018.10.24_Newton(01).blend](https://archive.blender.org/developer/F5218748/blender_2018.10.24_Newton_01_.blend)

Predrag Lazic commented

2018-10-25 00:57:24 +02:00

Added subscriber: @particl3s

Philipp Oeser commented

2018-10-25 10:31:19 +02:00

Added subscriber: @lichtwerk

Philipp Oeser self-assigned this 2018-10-25 10:31:19 +02:00

Philipp Oeser commented

2018-10-25 10:31:19 +02:00

regarding scaling: this worked in 2.79b, but shows same reported behavior in 2.79 master
regarding scaling behavior (which seems to have swapped axis): this also changed somewhere along 2.79b and 2.79 master
So those master changes are in 2.8 as well...

Will have a look when that happened (and for a possible reason), confirming for now...

regarding scaling: this worked in 2.79b, but shows same reported behavior in 2.79 master regarding scaling behavior (which seems to have swapped axis): this also changed somewhere along 2.79b and 2.79 master So those master changes are in 2.8 as well... Will have a look when that happened (and for a possible reason), confirming for now...

Philipp Oeser commented

2018-10-25 12:06:24 +02:00

behavior changed in ec76f38b09 and again in a9509a2f8a

Looking at fix now...

behavior changed in ec76f38b09 and again in a9509a2f8a Looking at fix now...

Philipp Oeser removed their assignment 2018-10-25 16:01:02 +02:00

Alexander Gavrilov was assigned by Philipp Oeser

2018-10-25 16:01:02 +02:00

Philipp Oeser commented

2018-10-25 16:01:02 +02:00

Added subscriber: @angavrilov

Philipp Oeser commented

2018-10-25 16:01:02 +02:00

Note: afaics, this is not related to proxyfying, same behavior can be observed in the file itself.
It is just that the Maintain Volume constraint has changed its behavior.

This happens only if the Free Axis specified in the constraint is actually locked on the bone itself (this is the case in the file).
If I understand correctly, this setup will actually have no Volume maintaining effect at all, if you try this in 2.79b you can remove the constraint and scaling behaves exactly the same as with the constraint.
@particl3s : any reason it is there at all?

Now with the mentioned commits in effect [also in 2.8], this will end up looking like scaling wont happen at all, but afaics the doings of the constraint just compensate the normal scaling so it ends up being same size.
I wouldnt be sure what the expected behavior in this case would actually be?

I would like to hand this of to @angavrilov (or at least ask for his opinion), as this might not be a bug at all in the end...

Note: afaics, this is not related to proxyfying, same behavior can be observed in the file itself. It is just that the `Maintain Volume` constraint has changed its behavior. This happens only if the `Free Axis` specified in the constraint is actually locked on the bone itself (this is the case in the file). If I understand correctly, this setup will actually have no Volume maintaining effect at all, if you try this in 2.79b you can remove the constraint and scaling behaves exactly the same as with the constraint. @particl3s : any reason it is there at all? Now with the mentioned commits in effect [also in 2.8], this will end up looking like scaling wont happen at all, but afaics the doings of the constraint just compensate the normal scaling so it ends up being same size. I wouldnt be sure what the expected behavior in this case would actually be? I would like to hand this of to @angavrilov (or at least ask for his opinion), as this might not be a bug at all in the end...

Philipp Oeser changed title from ~~2.79 -> 2.8 rig proxy unexpected behaviour.~~ to 2.79 -> 2.8 Maintain Volume constraint unexpected behaviour.

2018-10-25 16:02:35 +02:00

Alexander Gavrilov commented

2018-10-25 16:12:33 +02:00

Well, you'd expect from the name that the whole point of the constraint is to maintain volume, i.e. sxsysz = const; and in 2.79 it wasn't the case: the only situation where 2.79 worked correctly was when sx = sy = sz, i.e. uniform scaling.

Well, you'd expect from the name that the whole point of the constraint is to maintain volume, i.e. sx*sy*sz = const; and in 2.79 it wasn't the case: the only situation where 2.79 worked correctly was when sx = sy = sz, i.e. uniform scaling.

Predrag Lazic commented

2018-10-25 18:00:57 +02:00

@lichtwerk The reason it's there is out of habit. Simply seemed like the right thing to do. Looks like I made a mistake.

Philipp Oeser commented

2018-10-25 20:59:20 +02:00

Changed status from 'Open' to: 'Resolved'

Philipp Oeser closed this issue

2018-10-25 20:59:20 +02:00

Philipp Oeser commented

2018-10-25 20:59:20 +02:00

So looks like we can close this then?

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2.79 -> 2.8 Maintain Volume constraint unexpected behaviour. #57376