Improved 3D transform ingestion & affine transform support

[Wumpf]

Transform 3D type now captures a variety of properties as-is:

• 🆕 direction child/parent vs parent/child
• rotation:
  • 🆕 axis angle
    • 🆕 preserves radian/degree
  • quaternion
• 🆕 scale
  • uniform
  • per-axis
• translation
• 🆕 scale/skew/rotation as matrix3x3

The viewer UI reflects this:
https://github.com/rerun-io/rerun/assets/1220815/412be346-b7b7-4c90-8b33-9089aadb7b13

Some transforms in action that we didn't expose so far:
https://github.com/rerun-io/rerun/assets/1220815/f27d6e3f-024b-4989-bea8-4ce95be3f8b0

Component split-up

• Pinhole
• Transform3D

  • Assumed to be affine. Not named such for ergonomic reasons

    pub struct Transform3D {
        pub transform: Transform3DRepr,
    		pub from_parent: bool,
    }
    
    pub enum Transform3DRepr {
        TranslationAndMat3(TranslationAndMat3),
        TranslationRotationScale(TranslationRotationScale3D),
        // TODO(andreas): Raw 4x4 matrix.
    }

• DisconnectedSpace

Python API changes

• log_rigid3 deprecated

• log_unknown deprecated

• log_pinhole unchanged

• log_disconnected_space

• log_transform3d Example:

  rr.log_transform3d(
    "transform_test/child_from_parent_mat3",
    rr.TranslationAndMat3((123, 456, 789), np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])),
    from_parent=True,
  )
  rr.log_transform3d("transform_test/parent_from_child_mat3",
  	rr.TranslationAndMat3((123, 456, 789))
  )
  rr.log_transform3d("transform_test/empty_translation_mat3",
  	rr.TranslationAndMat3()
  )
  rr.log_transform3d("transform_test/translation_only",
  	rr.TranslationRotationScale3D((1, 2, 3))
  )
  rr.log_transform3d("transform_test/quaternion_only",
  	rr.TranslationRotationScale3D(rotation=rr.Quaternion(xyzw=(0, 0, 0, 1))
  )
  rr.log_transform3d(
    "transform_test/axis_angle_degrees_only",
    rr.RotationAxisAngle((0, 1, 0), degrees=10),
  )
  # TODO: rr.Translation3D, also on native - enum Translation3D { None, Vec3(Vec3) }|
  # TODO: rr.Scale3D
  rr.log_transform3d(
    "transform_test/axis_angle_radians_only",
    rr.RotationAxisAngle((0, 0, 1), radians=1),
  )
  rr.log_transform3d(
    "transform_test/scale_uniform_only",
    rr.TranslationRotationScale3D(scale=rr.Scale3D(2)),
  )
  rr.log_transform3d(
    "transform_test/scale_vector",
    rr.TranslationRotationScale3D(scale=(1, 2, 3)),
  )

Future Work

• Document & test Transform3D and Pinhole on the same entity (generally working now!)
• Python utility rr.transform(rotation=, translation=, matrix=)
• Support Matrix4 on transform3d
  • warning if not affine? etc.
• Support euler angles?
• Support None to specify unknown Pinhole/Transform3d
• Support other Quaternion representations (open question whether this time we swizzle before ingesting, or add another enum. low stakes decision)
  • Accept quaternions in both wxyz and xyzw format #883
• Direct support for scipi datatypes!
• Allow to pass in interfaces - anything that implements some interface (that e.g. specifies translation) can be passed in to rr.log_transform3d

---

Fixes #1956

• Support affine transformations (allow scaling!) #1956

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)

PR Build Summary: https://build.rerun.io/pr/2102

[Wumpf]

Read for review now!

Can't repro python linting errors locally, must be version dependent. Those lints don't make sense to me though - sounds like mypi has a built-in quaternion type..? Any advice very welcome
https://github.com/rerun-io/rerun/actions/runs/5006419878/jobs/8971679858?pr=2102

[emilk]

We also need to update https://www.rerun.io/docs/concepts/spaces-and-transforms

[jleibs]

😭 oof -- the need to jump through these hoops is so painful

[jleibs]

something is wrong here...

Suggested change

	rr.Translation3D(
	trimesh.transformations.translation_from_matrix(world_from_mesh, world_from_mesh[0:3, 0:3])
	),
	rr.TranslationAndMat3(
	rr.Translation3D(
	trimesh.transformations.translation_from_matrix(world_from_mesh)
	),
	world_from_mesh[0:3, 0:3])
	),