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scipy Rotation.from_euler("XYZ", ...) is the intrinsic (rotating-frame)
convention R = Rx @ Ry @ Rz, while DROID stores euler angles in the
extrinsic fixed-frame "xyz" convention R = Rz(yaw) @ Ry(pitch) @ Rx(roll)
(see droid/misc/transformations.py in the DROID codebase). Only the
extrinsic convention matches tfg.rotation_matrix_3d.from_euler and the
eef_9d statistics of the released pretrained checkpoints, so the previous
code reconstructed a different rotation per timestep.
- gr00t/data/state_action/droid_frame.py: use scipy "xyz" (lowercase)
and document the load-bearing convention difference.
- examples/DROID/main_gr00t.py: sync the vendored mirror.
- scripts/verify_droid_rotation_correction.py: verify against "xyz".
- scripts/download_droid_sample.py: clarify the euler convention comment.
- demo_data/droid_sample: regenerate eef_9d columns and stats with the
corrected convention (raw cartesian_position columns untouched).
- tests: pin the extrinsic convention and guard the vendored mirror.
Author
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cc. @ryhalabi |
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Summary
Rotation.from_euler("XYZ", ...)in scipy is the intrinsic (rotating-frame) conventionR = Rx @ Ry @ Rz, but DROID stores euler angles in the extrinsic fixed-framexyzconventionR = Rz(yaw) @ Ry(pitch) @ Rx(roll)(seedroid/misc/transformations.py, which usesR.from_euler("xyz", ...)/.as_euler("xyz")throughout). The extrinsic convention is also whattfg.rotation_matrix_3d.from_eulercomputes (R = Rz @ Ry @ Rx).The current code used uppercase
"XYZ"while documenting it as "extrinsic" and "equivalent to tfg" — the comment and the call contradicted each other. Since the two conventions produce different rotation matrices for the same angle triple (median ~46° of angular distortion on real DROID data), the pipeline reconstructed the wrong eef rotation per timestep, and it did not match theeef_9dstatistics of the released pretrained checkpoints (nvidia/GR00T-N1.7-3B,nvidia/GR00T-N1.7-DROID— computed under the extrinsic/tfg convention).Changes
gr00t/data/state_action/droid_frame.py: switch to scipy"xyz"(lowercase) and document why the spelling is load-bearing.examples/DROID/main_gr00t.py: sync the vendored mirror (dataset builder / real-robot client).scripts/verify_droid_rotation_correction.py: verify against the extrinsic convention.scripts/download_droid_sample.py: clarify the convention comment.demo_data/droid_sample: regenerateeef_9dcolumns andmeta/stats.json/meta/relative_stats.jsonwith the corrected convention (rawcartesian_positioncolumns are untouched; non-eef_9dstats dimensions are byte-identical).tests/gr00t/data/state_action/test_droid_frame.pypins the extrinsic/tfg convention (and asserts the intrinsic one differs);tests/examples/test_droid.pygains an AST guard that the vendored mirror stays in sync.Verification
pytest tests/gr00t/data/state_action/test_droid_frame.py tests/examples/test_droid.py -m "not gpu": 14 passed.eef_9dequalsR.from_euler("xyz", euler) @ DROID_EEF_ROTATION_CORRECTexactly for all timesteps.ruff check/ruff formatclean on all touched files.Note
This restores the convention used by the DROID example before commit
c5cadf5(which switched the inference client from"xyz"to"XYZ"based on the incorrect scipy/tfg equivalence claim). Anyone who has post-trained with the interim convention should regenerate their processed dataset with the updated scripts.