Rotation issues with MMB constraints On #116448

New Issue

Toni-Bratincevic · 2023-12-21T20:26:09+01:00

Toni-Bratincevic commented

2023-12-21 20:26:09 +01:00

System Information
Operating system: Windows 11
Graphics card: Nvidia ADA 6000
CPU: AMD Threadripper 3960x

Blender Version
Broken: 4.02

Short description of error
When rotation objects with MMB for constraint to certain axis, I am getting rotation imperfections. For example, I click on the object and start rotating it and then MMB to constraint it to X axis for example, when I finish my rotation, it will add some small numbers to Y or Z axis. This does not happen when you lock your axis constraint with X Y or Z keys instead of using MMB. But I am using MMB since it is much faster and more intuitive, so I get a lot of these imperfection which I did not see in other 3D apps.
As I am modeling and doing a lot of rotations this gets worse over time to the point where many of my faces/edges are misaligned, so this leads to other issues like using Mirror modifier.

Exact steps for others to reproduce the error

Click on an object and start rotating it.
While rotating, use the MMB to constrain the rotation to a specific axis, such as the X axis.
Finish the rotation and observe if any small numbers are added to the Y or Z axis.
Compare this behavior to locking the axis constraint with the X, Y, or Z keys instead of using the MMB.

Thank you,
Toni Bratincevic

**System Information** Operating system: Windows 11 Graphics card: Nvidia ADA 6000 CPU: AMD Threadripper 3960x **Blender Version** Broken: 4.02 **Short description of error** When rotation objects with MMB for constraint to certain axis, I am getting rotation imperfections. For example, I click on the object and start rotating it and then MMB to constraint it to X axis for example, when I finish my rotation, it will add some small numbers to Y or Z axis. This does not happen when you lock your axis constraint with X Y or Z keys instead of using MMB. But I am using MMB since it is much faster and more intuitive, so I get a lot of these imperfection which I did not see in other 3D apps. As I am modeling and doing a lot of rotations this gets worse over time to the point where many of my faces/edges are misaligned, so this leads to other issues like using Mirror modifier. **Exact steps for others to reproduce the error** - Click on an object and start rotating it. - While rotating, use the MMB to constrain the rotation to a specific axis, such as the X axis. - Finish the rotation and observe if any small numbers are added to the Y or Z axis. - Compare this behavior to locking the axis constraint with the X, Y, or Z keys instead of using the MMB. Thank you, Toni Bratincevic

blender_ZaWRHNRbQX.png

225 KiB

Toni-Bratincevic added the

labels 2023-12-21 20:26:10 +01:00

Germano Cavalcante commented

2023-12-21 23:46:04 +01:00

I tried to reproduce the problem using Blender version 4.02, but I couldn't encounter the same behavior.

In Blender, the rotation constraint with X, Y, or Z should not behave differently than with the MMB. The underlying code works the same for both methods of constraint.

It's important to note that imprecision issues can arise when working with 32-bit numbers due to floating precision limitations. Unfortunately, this is a known issue in Blender.

To further investigate the problem, could you please double-check if the same imprecision really doesn't occurs when using the X, Y, and Z constraints? Additionally, if possible, could you provide more specific steps to help us replicate the issue?

I tried to reproduce the problem using Blender version 4.02, but I couldn't encounter the same behavior. In Blender, the rotation constraint with X, Y, or Z should not behave differently than with the MMB. The underlying code works the same for both methods of constraint. It's important to note that imprecision issues can arise when working with 32-bit numbers due to floating precision limitations. Unfortunately, this is a known issue in Blender. To further investigate the problem, could you please double-check if the same imprecision really doesn't occurs when using the X, Y, and Z constraints? Additionally, if possible, could you provide more specific steps to help us replicate the issue?

Germano Cavalcante added

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labels 2023-12-21 23:46:13 +01:00

Toni-Bratincevic commented

2023-12-22 20:27:09 +01:00

Hi Germano thank you for reaching to me so quickly. I recorded a small session showing this issue, hopefully it helps. It looks like it does happen even if I lock axis with X Y or Z keys but it happens more often if I do it with MMB.

2023-12-22 11-19-04.mp4

70 MiB

Germano Cavalcante commented

2023-12-22 21:29:55 +01:00

From what I saw in the video, it seems that the constraint with MMB behaves the same way as using X, Y, or Z.
After the second 31 of the video, the Cube's rotation is confirmed with a slight tilt, so it is expected that the inaccuracy will become even worse from there.

Based on what I can tell, this is actually an issue with Blender's inherent inaccuracy. It is a known limitation and has been reported multiple times in the past. Some related reports include:

#111611: Object rotation inaccuracy in orthographic view
#71535: Rotating an object in front or back view adds value to X and Z
#71438: Align to Transform Orientation precision issue
#60305: Rotation bug

Unfortunately, there isn't a specific solution at the moment :\

From what I saw in the video, it seems that the constraint with MMB behaves the same way as using X, Y, or Z. After the second 31 of the video, the Cube's rotation is confirmed with a slight tilt, so it is expected that the inaccuracy will become even worse from there. Based on what I can tell, this is actually an issue with Blender's inherent inaccuracy. It is a known limitation and has been reported multiple times in the past. Some related reports include: - #111611: Object rotation inaccuracy in orthographic view - #71535: Rotating an object in front or back view adds value to X and Z - #71438: Align to Transform Orientation precision issue - #60305: Rotation bug Unfortunately, there isn't a specific solution at the moment :\

Toni-Bratincevic commented

2023-12-27 19:24:16 +01:00

Hi Germano.
Thank you for explaining this issue. I will try to be aware of this limitation in the future in case I need to correct it.
But I was wondering if there is a small number added to the rotation like 0.0001 why is Blender not rounding this to 0? No user would probably rotate by that angle? I am also wondering if rotation is locked to one axis, why is it adding number to the other axis?

I deeply appreciate reaching out to me so fast. I didn't expect this fast response. Thank you!

Hi Germano. Thank you for explaining this issue. I will try to be aware of this limitation in the future in case I need to correct it. But I was wondering if there is a small number added to the rotation like 0.0001 why is Blender not rounding this to 0? No user would probably rotate by that angle? I am also wondering if rotation is locked to one axis, why is it adding number to the other axis? I deeply appreciate reaching out to me so fast. I didn't expect this fast response. Thank you!

Toni-Bratincevic closed this issue

2023-12-27 19:24:18 +01:00

Blender Bot added

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labels 2023-12-27 19:24:21 +01:00

Germano Cavalcante commented

2023-12-27 21:10:05 +01:00

I am also wondering if rotation is locked to one axis, why is it adding number to the other axis?

Interesting suggestion, however, implementing this feature would require considering certain conditions:

The elements being transformed would need to support and have Euler rotation enabled
each selected object's transformation would need to be in the Local space (individually).

While it is possible to implement this, it would add complexity to the code and may not resolve all cases.

But in fact, it seems to be viable.

> I am also wondering if rotation is locked to one axis, why is it adding number to the other axis? Interesting suggestion, however, implementing this feature would require considering certain conditions: - The elements being transformed would need to support and have Euler rotation enabled - each selected object's transformation would need to be in the Local space (individually). While it is possible to implement this, it would add complexity to the code and may not resolve all cases. But in fact, it seems to be viable.

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Rotation issues with MMB constraints On #116448