[visualization] Add frame (aka triad) visualization function

[jwnimmer-tri]

Closes #17170.

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This change is 

[mitiguy]

Reviewable status: needs platform reviewer assigned, needs at least two assigned reviewers

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bindings/pydrake/visualization/_model_visualizer.py line 532 at r1 (raw file):

):
    """
    Adds illustration geometry representing the given coordinate frame, with

FYI It seems the word "coordinate" is unnecessary. In the context of Drake, it is unclear how a coordinate frame differs from a frame. Consider removing it.

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bindings/pydrake/visualization/_model_visualizer.py line 547 at r1 (raw file):

      radius: the radius of each axis in meters.
      opacity: the opacity each axes, between 0.0 and 1.0.
      X_FT: the pose of the triad frame T in the frame_id frame F.

FYI consider:

X_FT: rigid transform relating frame T and frame F.

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bindings/pydrake/visualization/_model_visualizer.py line 548 at r1 (raw file):

      opacity: the opacity each axes, between 0.0 and 1.0.
      X_FT: the pose of the triad frame T in the frame_id frame F.
      name: the added geometries will have names "{name} x-axis", etc.

FYI Wondering if x-axis associates with a line or a unit vector (a direction) -- or if there is sufficient context that it is irrelevant? If the x-axis is a unit vector and the body name is B, I typically use names such as Bx, By, Bz for the associated unit vectors -- or if enough unicode bandwidth 𝗕x 𝗕y 𝗕ᴢ.

[sherm1]

Reviewable status: 1 unresolved discussion, needs platform reviewer assigned, needs at least two assigned reviewers (waiting on @jwnimmer-tri and @mitiguy)

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bindings/pydrake/visualization/_model_visualizer.py line 564 at r1 (raw file):

        geom_name = f"{name} {char}-axis"
        p_TG = 0.5 * length * eye[i]
        R_TG = AngleAxis(angle=np.pi/2, axis=eye[1-i])

BTW am I interpreting eye[1-i] correctly: it maps x->y, y->x and z to itself? And is that the intent?

[jwnimmer-tri]

Reviewable status: 1 unresolved discussion, needs platform reviewer assigned, needs at least two assigned reviewers (waiting on @mitiguy and @sherm1)

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bindings/pydrake/visualization/_model_visualizer.py line 564 at r1 (raw file):

Am I interpreting eye[1-i] correctly: it maps x->y, y->x and z to itself

Yes!

And is that the intent?

Yes. R_TG rotates a cylinder aligned with the z axis to instead align with the ith axis. When i == 2, it spins the cylinder around the z axis, but this is a no-op (for a uniformly textured cylinder).

[sherm1]

Reviewable status: 1 unresolved discussion, needs platform reviewer assigned, needs at least two assigned reviewers (waiting on @jwnimmer-tri and @mitiguy)

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bindings/pydrake/visualization/_model_visualizer.py line 564 at r1 (raw file):

Previously, jwnimmer-tri (Jeremy Nimmer) wrote…

Am I interpreting eye[1-i] correctly: it maps x->y, y->x and z to itself

Yes!

And is that the intent?

Yes. R_TG rotates a cylinder aligned with the z axis to instead align with the ith axis. When i == 2, it spins the cylinder around the z axis, but this is a no-op (for a uniformly textured cylinder).

👍

[jwnimmer-tri]

Reviewable status: needs platform reviewer assigned, needs at least two assigned reviewers (waiting on @mitiguy and @sherm1)

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bindings/pydrake/visualization/_model_visualizer.py line 548 at r1 (raw file):

Previously, mitiguy (Mitiguy) wrote…

FYI Wondering if x-axis associates with a line or a unit vector (a direction) -- or if there is sufficient context that it is irrelevant? If the x-axis is a unit vector and the body name is B, I typically use names such as Bx, By, Bz for the associated unit vectors -- or if enough unicode bandwidth 𝗕x 𝗕y 𝗕ᴢ.

The illustration geometry is not really a unit vector.

[rpoyner-tri]

+@rpoyner-tri feature.

Reviewable status: LGTM missing from assignee rpoyner-tri(platform), needs at least two assigned reviewers

[rpoyner-tri]

Reviewable status: 1 unresolved discussion, LGTM missing from assignee rpoyner-tri(platform), needs at least two assigned reviewers (waiting on @jwnimmer-tri)

a discussion (no related file):
Are there any recommended manual tests for visuals?

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[jwnimmer-tri]

Reviewable status: 1 unresolved discussion, LGTM missing from assignee rpoyner-tri(platform), needs at least two assigned reviewers (waiting on @rpoyner-tri)

a discussion (no related file):

Previously, rpoyner-tri (Rick Poyner (rico)) wrote…

Are there any recommended manual tests for visuals?

My nominal manual test is always just to run the model file given in the help string, in this case with triads turned on:

bazel run //tools:model_visualizer -- package://drake/manipulation/models/iiwa_description/iiwa7/iiwa7_with_box_collision.sdf --visualize_frames

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[rpoyner-tri]

nittery

Reviewed 1 of 2 files at r1, 5 of 5 files at r2, all commit messages.
Reviewable status: 1 unresolved discussion, needs at least two assigned reviewers (waiting on @jwnimmer-tri)

a discussion (no related file):

Previously, jwnimmer-tri (Jeremy Nimmer) wrote…

My nominal manual test is always just to run the model file given in the help string, in this case with triads turned on:

bazel run //tools:model_visualizer -- package://drake/manipulation/models/iiwa_description/iiwa7/iiwa7_with_box_collision.sdf --visualize_frames

Looks good. I pondered whether there was a way with current on-screen controls to conveniently turn the frames on/off as a layer or even individually, but didn't really succeed in finding one. Maybe can be addressed in follow-up work?

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bindings/pydrake/visualization/_triad.py line 26 at r2 (raw file):

    radius: float = 0.005,
    opacity: float = 0.9,
    X_FT: RigidTransform = RigidTransform(),

nit recall that the default values are global lifetime and mutable. I can't see a problem with the current implementation here (no modifications of X_FT), but I will confess a shiver goes down my spine.

[jwnimmer-tri]

Reviewable status: needs at least two assigned reviewers (waiting on @rpoyner-tri)

a discussion (no related file):

Maybe can be addressed in follow-up work?

Yup. We could do it the same way that we are going to do the inertia visualization. It requires one new capability from MeshcatVisualizer so I'm going to wait for inertia to land first.

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bindings/pydrake/visualization/_triad.py line 26 at r2 (raw file):

Previously, rpoyner-tri (Rick Poyner (rico)) wrote…

nit recall that the default values are global lifetime and mutable. I can't see a problem with the current implementation here (no modifications of X_FT), but I will confess a shiver goes down my spine.

I had actually thought about that, but somehow misremembered that RigidTransform was immutable so dismissed it out of hand. Oops.

[rpoyner-tri]

+@ggould-tri for Monday platform review.

Reviewed 1 of 1 files at r3, all commit messages.
Reviewable status: LGTM missing from assignee ggould-tri(platform) (waiting on @ggould-tri)

[ggould-tri]

Reviewed 1 of 2 files at r1, 4 of 5 files at r2, 1 of 1 files at r3, all commit messages.
Reviewable status: complete! all discussions resolved, LGTM from assignees rpoyner-tri(platform),ggould-tri(platform) (waiting on @jwnimmer-tri)