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nutonomy / nuscenes-devkit

The devkit of the nuScenes dataset.
https://www.nuScenes.org
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Point Acquisition Order in .pcd files #973

Closed enrico-stauss closed 10 months ago

enrico-stauss commented 10 months ago

Hi, I just wanted to know wether I can assume that points in the first rows of the .pcd files are recorded before points towards the end of the file. Or possibly the other way round.

Thanks in advance and kind regards Enrico

whyekit-motional commented 10 months ago

@enrlc0 there's no specific ordering to the points in the .pcd files

enrico-stauss commented 10 months ago

OK thanks @whyekit-motional! Can you maybe tell me instead if the sensor rotates clockwise (mathematically negative) or counterclockwise (mathematically positive)?

whyekit-motional commented 10 months ago

@enrlc0 I believe it should be clockwise, when looking down at the top of the lidar (however, it might be best to confirm with the manual for the Velodyne HDL32E, which is the lidar used in nuScenes)

enrico-stauss commented 10 months ago

@whyekit-motional thanks for the hint, until now I had only looked at the spec sheet but the full manual indicates that the rotational direction is mathematically negative (clockwise if viewed from above) even though it is not entirely clear as the graphic misses some annotation.

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