Equal Vs. Not Equal does not have opposite effect. #98317

New Issue

Gerstmann Bradley · 2022-05-22T15:54:26+02:00

Gerstmann Bradley commented

2022-05-22 15:54:26 +02:00

System Information
Operating system: Windows-10-10.0.17134-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 970M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 466.11

Blender Version
Broken: version: 3.2.0 Beta, branch: master, commit date: 2022-05-20 15:07, hash: bf352df27a
Worked: (newest version of Blender that worked as expected)

Short description of error
[Equal Not Equal].mp4
Equal Not Equal.blend

**System Information** Operating system: Windows-10-10.0.17134-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 970M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 466.11 **Blender Version** Broken: version: 3.2.0 Beta, branch: master, commit date: 2022-05-20 15:07, hash: `bf352df27a` Worked: (newest version of Blender that worked as expected) **Short description of error** [[Equal Not Equal].mp4](https://archive.blender.org/developer/F13097630/_Equal_Not_Equal_.mp4) [Equal Not Equal.blend](https://archive.blender.org/developer/F13097629/Equal_Not_Equal.blend)

Gerstmann Bradley commented

2022-05-22 15:54:26 +02:00

Added subscriber: @Bradley_G

Omar Emara commented

2022-05-23 10:39:55 +02:00

Added subscriber: @OmarEmaraDev

Omar Emara commented

2022-05-23 10:39:55 +02:00

Changed status from 'Needs Triage' to: 'Confirmed'

Omar Emara commented

2022-05-23 10:39:55 +02:00

The Not Equal code uses the expression abs(a.x - b.x) > epsilon && abs(a.y - b.y) > epsilon && abs(a.z - b.z) > epsilon while it probably should be abs(a.x - b.x) > epsilon || abs(a.y - b.y) > epsilon || abs(a.z - b.z) > epsilon.

The Not Equal code uses the expression `abs(a.x - b.x) > epsilon && abs(a.y - b.y) > epsilon && abs(a.z - b.z) > epsilon` while it probably should be `abs(a.x - b.x) > epsilon || abs(a.y - b.y) > epsilon || abs(a.z - b.z) > epsilon`.

Philipp Oeser commented

2022-05-23 10:48:13 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-05-23 10:48:13 +02:00

Not sure I am getting the usecase right, these should all be equal, right (we are comparing the same points so to speak)? So we are in the realm of numerical floating point imprecissions?

Philipp Oeser commented

2022-05-23 10:49:50 +02:00

Thx checking @OmarEmaraDev

Gerstmann Bradley commented

2022-05-23 12:23:31 +02:00

No, they shouldn't be all equal.
Given two spheres with the same radius, Geometry Proximity's positional output should be the same as sphere's own origin, only if there's no intersection.
When there's intersection, position will be attracted by the other sphere's origin.
In this bug report, "Not Equal" is giving wrong result, because it should have selected these intersecting vectors, as you see in "Equal Not".

No, they shouldn't be all equal. Given two spheres with the same radius, Geometry Proximity's positional output should be the same as sphere's own origin, only if there's no intersection. When there's intersection, position will be attracted by the other sphere's origin. In this bug report, "Not Equal" is giving wrong result, because it should have selected these intersecting vectors, as you see in "Equal Not".

blender-admin commented

2022-05-24 09:49:58 +02:00

This issue was referenced by e07b1b8316

This issue was referenced by e07b1b8316392ebf3c51a4671d8b56dc4b222f02

Jacques Lucke commented

2022-05-24 09:50:21 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Jacques Lucke closed this issue

2022-05-24 09:50:21 +02:00

Jacques Lucke self-assigned this 2022-05-24 09:50:21 +02:00

Jeff Knox commented

2023-12-05 20:22:14 +01:00

This is a little confusing from a mathematical perspective. All other operations in the Compare node are of the form:
all(A.component <op> B.component)

But now the Not Equal operation is of the form:
any(A.component <op> B.component)

I understand that this seems to be more intuitive for non-mathematically inclined users, but I wonder if the wording could be made more clear that this is happening. It may not be practical because something like Not Equal (any component) is too verbose to fit in the node.

This is a little confusing from a mathematical perspective. All other operations in the `Compare` node are of the form: `all(A.component <op> B.component)` But now the `Not Equal` operation is of the form: `any(A.component <op> B.component)` I understand that this seems to be more intuitive for non-mathematically inclined users, but I wonder if the wording could be made more clear that this is happening. It may not be practical because something like `Not Equal (any component)` is too verbose to fit in the node.

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Equal Vs. Not Equal does not have opposite effect. #98317