[QUESTION] Retrieve absolute positions of the object with respect to the world frame about hydra HOT 3 CLOSED

Thank you for your interest! It's worth noting that convention-wise, the bounding box fields follow pretty exactly what PCL provides. If you're extracting axis-aligned bounding boxes (the default for uhumans2), the min and max will be expressed in the world frame, and if you're extracting oriented bounding boxes (or the z-only oriented bounding boxes) the min and max are expressed slightly differently (see here). The argument use_oriented_bounding_boxes toggles between axis-aligned (if false) and the z-only oriented bounding boxes (if true). This may be a source of confusion.

What you're seeing might also have to do with synchronization issues between the frontend and the backend (in particular, the backend might not have access to the newest mesh that the frontend provides when updating the scene graph). However, I'm not sure that these issues would manifest in the way you're seeing.

Can you share more information about what you're seeing? How different is the position from the bounding box? Is it limited to a certain set of object nodes (i.e. the ones in the active window), or is it all of them? Saving the scene graph (at the point where you're seeing the issue) and then plotting the resulting objects and bounding boxes may be a good way to look at this in a more principled manner.

Are the objects being scaled before visualized, or do bounding boxes have some other reference coordinate frame? Then, is the position stored in the scene graph the ground-truth position?

No, the objects and bounding box are being visualized as is, i.e. the bounding boxes are CUBE markers drawn around attributes.bounding_box.world_P_center with scale attributes.bounding_box.max - attributes.bounding_box.min, and the node markers are drawn around attributes.position. Both use the current estimates (we don't have access to ground truth object information inside Hydra).

from hydra.

Apologies for my delayed reply. Thanks for your prompt response. I checked again, and it looks like I was visualizing it wrong. Thanks for the heads up on using oriented bounding boxes; it did help me to fix the issue. Thanks again!

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Great, glad that you found the issue! I'm going to close this for now, feel free to reopen if anything related pops up

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