Pivot point broken after scaling a flat object to 0 in a dimension #57767

New Issue

Andrew · 2018-11-10T18:31:19+01:00

Andrew commented

2018-11-10 18:31:19 +01:00

Windows 10

Broken: 2.80 2c2c996a1b
Worked: 2.79

Pivot point is broken after scaling an already flat object to 0 in its flat dimension.
After that, only 'individual origins' seems to work. All other pivot point modes seem to default to the object origin.

Steps to reproduce:

Open blender.
Add bezier (or circle, etc) (shift + a > curve > bezier).
In object mode, scale z to 0 (s + z + 0 + enter)
Enter edit mode (tab)
Select one point (right-click)
Make sure pivot point is set to Median Point (hold period > median point)
Optionally, switch to top-down orthographic (click ortho z / numpad-7)
Rotate selection (r)

Windows 10 Broken: 2.80 2c2c996a1b2 Worked: 2.79 Pivot point is broken after scaling an already flat object to 0 in its flat dimension. After that, only 'individual origins' seems to work. All other pivot point modes seem to default to the object origin. Steps to reproduce: - Open blender. - Add bezier (or circle, etc) (shift + a > curve > bezier). - In object mode, scale z to 0 (s + z + 0 + enter) - Enter edit mode (tab) - Select one point (right-click) - Make sure pivot point is set to Median Point (hold period > median point) - Optionally, switch to top-down orthographic (click ortho z / numpad-7) - Rotate selection (r) ![image.png](https://archive.blender.org/developer/F5479848/image.png)

Andrew commented

2018-11-10 18:31:19 +01:00

Added subscriber: @cs32

Philipp Oeser commented

2018-11-12 12:07:16 +01:00

Added subscriber: @lichtwerk

Philipp Oeser self-assigned this 2018-11-12 12:07:16 +01:00

Philipp Oeser commented

2018-11-12 12:07:16 +01:00

Confirmed, will have a look...

blender-admin commented

2019-05-05 16:04:10 +02:00

This issue was referenced by 036e95bb21

This issue was referenced by 036e95bb21fa32ea6f30a32e7892af42c44cfa5a

Philipp Oeser commented

2019-05-06 10:10:42 +02:00

OK, had a look at this again and here are (some) findings:

first off a little detour [just as a background, nothing wrong here...]

since the introduction of multi-object-editing [or specifically 844a17a3d9], each TransDataContainer stores matrices [4x4, 3x3, ..., inverse matrix in imat,... derrived from the objects obmat]
prior to above commit, those matrices were computed "on demand" all over the place
now for e.g editmode above local matrices are used also for converting the global transform center to the local transform center, see calculateCenterLocal()

now to where this fails:

a scale of zero in a matrix is not invertible
2.79 suffers the same [unsolvable] problem, BUT:
matrix inversion was changed in 01c75c3765 from own code to EIGEN for performance reasons
if matrix inversion fails in EIGEN, it will return a zero matrix (this will result in a local transform center of 0/0/0 all the time)
if matrix inversion failed in previous blender code, it would do something 'smart' and return a 'partially inverted' matrix [everything inverted, failing components set to 1]

So my suggestion to workaround this situation would be to bring back the "old" invert_m4_m4() and use that as fallback if EIGEN fails.
This would make the local transform center appear correct, see D4804

other notes:

the helpline (see drawHelpline) is unaffected because it uses t->center_global
T_LOCAL_MATRIX seems unused? [was introduced in 844a17a3d9], see D4805 for removal

OK, had a look at this again and here are (some) findings: first off a little detour [just as a background, nothing wrong here...] - since the introduction of multi-object-editing [or specifically 844a17a3d9], each `TransDataContainer` stores matrices [4x4, 3x3, ..., inverse matrix in `imat`,... derrived from the objects `obmat`] - prior to above commit, those matrices were computed "on demand" all over the place - now for e.g editmode above local matrices are used also for converting the global transform center to the local transform center, see `calculateCenterLocal()` now to where this fails: - a scale of zero in a matrix is not invertible - 2.79 suffers the same [unsolvable] problem, BUT: - matrix inversion was changed in 01c75c3765 from own code to EIGEN for performance reasons - if matrix inversion fails in EIGEN, it will return a zero matrix (this will result in a local transform center of 0/0/0 all the time) - if matrix inversion failed in previous blender code, it would do something 'smart' and return a 'partially inverted' matrix [everything inverted, failing components set to 1] So my suggestion to workaround this situation would be to bring back the "old" `invert_m4_m4()` and use that as fallback if EIGEN fails. This would make the local transform center appear correct, see [D4804](https://archive.blender.org/developer/D4804) other notes: - the helpline (see `drawHelpline`) is unaffected because it uses `t->center_global` - `T_LOCAL_MATRIX` seems unused? [was introduced in 844a17a3d9], see [D4805](https://archive.blender.org/developer/D4805) for removal

Philipp Oeser commented

2019-05-07 10:50:58 +02:00

Changed status from 'Open' to: 'Resolved'

Philipp Oeser closed this issue

2019-05-07 10:50:58 +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

Pivot point broken after scaling a flat object to 0 in a dimension #57767