Upload README.md

README.md

@@ -557,6 +557,15 @@ Each entry in `transform_data` describes the pose of the object or component at
 
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+<h3 id="trajectories" style="font-size: 1.35em; margin-top: 0.75em; margin-bottom: 0.22em; line-height: 1.2; margin-left: 0;"><span style="display: inline-block; width: 1.08em;">•</span>Trajectories</h3>
+<div style="margin-left: 16px;">
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+Each sequence includes a same-named JSON file that records per-frame poses for selected dynamic objects in the world coordinate system. The file contains `sequence_info`, which stores basic sequence metadata such as frame count and `fps`, and `actors`, which stores object categories, asset index paths, actor types, and transformation data.
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+For `solid` actors, the object is treated as a single rigid body, and its pose sequence is stored in the actor-level `transform_data` field. For `interactable` actors, poses are computed separately for each component; therefore, the actor-level `transform_data` is empty, while each component stores its own poses under `components[component_name].transform_data`.
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+Each pose entry contains the frame index, timestamp, and transformation, including `location`, quaternion `rotation`, and `scale`.
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 <h3 id="cameras" style="font-size: 1.35em; margin-top: 0.75em; margin-bottom: 0.22em; line-height: 1.2; margin-left: 0;"><span style="display: inline-block; width: 1.08em;">•</span>Cameras</h3>