Rotating an object in front or back view adds value to X and Z #71535

System Information
Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX 750 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 388.13

Blender Version
Broken: version: 2.82 (sub 1), branch: master, commit date: 2019-11-12 13:30, hash: c69872bd2f
Worked: (optional)

Short description of error
[Rotating an object in orthographic front or back view adds value to X and Z,if you use hotkeys without specifying an axis of rotation.
If you rotate the object 90 degrees in Z, while rotating, deviations will be added for X and Y in other views, and indicating the axis of rotation does not help.]

Added subscriber: @roman-13

#101571 was marked as duplicate of this issue

#78623 was marked as duplicate of this issue

#78209 was marked as duplicate of this issue

#72035 was marked as duplicate of this issue

#71762 was marked as duplicate of this issue

Added subscriber: @MarcinTwarowski

Same in 2.81

Added subscriber: @Stan_Pancakes

Indicating the axis of rotation does help. With it, at "worst" you only get sign switching for 0. Without it, these small errors. For what it's worth, there was a time when this didn't happen (i.e. 2.49b) :)

Added subscriber: @mano-wii

Changed status from 'Open' to: 'Archived'

Although visually bad, this is normal since single precision floats only have 6-7 digits of precision.
Starting with Blender 2.80, default units are set (meters, degrees) and some have more decimal digits than "Blender Units".
So what is happening is that this inaccuracy is now seen.

There are ways to work around this problem internally by using operations that work with double precision.
But for this other things need to be taken into consideration (such as peformanse, code complexity, etc.).
This is a known limitation and not a priority at the moment.

I don't follow. Why would there even be a difference between R, Y (no extra decimals) and simply R in front view (extra decimals)?

In #71535#813863, @mano-wii wrote:
Although visually bad, this is normal since single precision floats only have 6-7 digits of precision.
Starting with Blender 2.80, default units are set (meters, degrees) and some have more decimal digits than "Blender Units".
So what is happening is that this inaccuracy is now seen.

There are ways to work around this problem internally by using operations that work with double precision.
But for this other things need to be taken into consideration (such as peformanse, code complexity, etc.).
This is a known limitation and not a priority at the moment.

If this is an inaccuracy, then why show it?
Better limit to 3 decimal places

Added subscribers: @MassimilianoPuliero, @lichtwerk

Afaict, constraining to a specified axis vs. using the ortho projection is not the same.
Dont think there is a special flag on the view that tells us we are in top/front/... but there could be ways to check [text info overlay knows at least...]

Not sure though if this would be a priority either.

Added subscribers: @brothermechanic, @vademenev

Changed status from 'Archived' to: 'Confirmed'

Added subscriber: @Juangra_Membata

Added subscriber: @awoug8h

Added subscriber: @ideasman42

Changed status from 'Confirmed' to: 'Archived'

Even though this behavior isn't ideal, closing as small numeric precision issues are an inherent problem with transforming in different spaces that get applied back.

Hey!
How about 2.49, where there is no this problem?
2020-11-04 18-00-46.mp4

In #71535#1048056, @brothermechanic wrote:
How about 2.49, where there is no this problem?

Probably because the interface limits to only 3 decimal units.
But the problem is still there because it is the one that causes the -0.000 (0 with a negative sign).

In #71535#1048120, @mano-wii wrote:

In #71535#1048056, @brothermechanic wrote:
How about 2.49, where there is no this problem?

Probably because the interface limits to only 3 decimal units.
But the problem is still there because it is the one that causes the -0.000 (0 with a negative sign).

We need that rounding to 2.9!

Added subscriber: @vojtech.salek

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Rotating an object in front or back view adds value to X and Z #71535