✨ Support multi-threading in the RayCastingScene function to commit scene

[sebastienmascha]

Support multi-threading in the RayCastingScene function to commit scene.

Type

• Bug fix (non-breaking change which fixes an issue): Fixes #
• New feature (non-breaking change which adds functionality). Resolves Support multi-threading in RaycastingScene::CastRays() #6050
• Breaking change (fix or feature that would cause existing functionality to not work as expected) Resolves #

Motivation and Context

See #6050

Checklist:

• I have run python util/check_style.py --apply to apply Open3D code style
  to my code.
• This PR changes Open3D behavior or adds new functionality.
  • Both C++ (Doxygen) and Python (Sphinx / Google style) documentation is
    updated accordingly.
  • I have added or updated C++ and / or Python unit tests OR included test
    results (e.g. screenshots or numbers) here.
• I will follow up and update the code if CI fails.
• For fork PRs, I have selected Allow edits from maintainers.

Description

See #6050

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This change is 

[update-docs]

Thanks for submitting this pull request! The maintainers of this repository would appreciate if you could update the CHANGELOG.md based on your changes.

[benjaminum]

@sebastienmascha Can you add a unit test checking if RayCastingScene is threadsafe?

Reviewable status: 0 of 1 files reviewed, all discussions resolved

[ssheorey]

Hi @sebastienmascha thanks for submitting this PR! Gentle reminder about addressing @benjaminum 's comment (add unit test).

[benjaminum]

@sebastienmascha Let us know if help is needed with the unit test

[benjaminum]

Reviewable status: 0 of 2 files reviewed, all discussions resolved

[ssheorey]

Strange unit test error in WIndows (OFF, ON, OFF, Release). Will merge and check if this re-occurs:

D:\a\Open3D\Open3D\cpp\tests\t\pipelines\registration\Registration.cpp(280): error: The difference between reg_colored_t.fitness_ and reg_colored_l.fitness_ is 0.20490959870645309, which exceeds 0.05, where
reg_colored_t.fitness_ evaluates to 0.71993973247096865,
reg_colored_l.fitness_ evaluates to 0.92484933117742174, and
0.05 evaluates to 0.050000000000000003.
D:\a\Open3D\Open3D\cpp\tests\t\pipelines\registration\Registration.cpp(282): error: The difference between reg_colored_t.inlier_rmse_ and reg_colored_l.inlier_rmse_ is 0.13259293800465694, which exceeds 0.02, where
reg_colored_t.inlier_rmse_ evaluates to 0.34763052771474739,
reg_colored_l.inlier_rmse_ evaluates to 0.21503758971009046, and
0.02 evaluates to 0.02.
[  FAILED  ] Registration/RegistrationPermuteDevices.ICPColored/0, where GetParam() = 8-byte object <00-00 00-00 00-00 00-00> (42341 ms)
[ RUN      ] Registration/RegistrationPermuteDevices.ICPPointToPlane/0