how to recover metric scale of harvested 3d assets?

[yueyunqingwu]

Thank you for open-sourcing the execlent work. I tried to insert a harvested vehicle gaussian ply in camera view, since the ply is normalized, the size of vehicle in rendered image mismatched which in gt image, the former is obvious smaller, it would be a problem in subsequent training stage. I'm wondering how do you solve it? how do you recover metric scale of harvested 3d assets? Thank you, i'm looking forward for your reply.

[bertaveira]

We did multiple methods to fix the size. First by figuring out which orientation fits best the proportions of the bounding box, then figuring out the scaling that fills the bounding box. These heuristics were done at scale in an automatic fashion. We also checked for volume density to try to guess which side is the front of the vehicle.

Unfortunately, the automatized process was not perfect so we then examined each harvested asset manually. We made a tiny GUI to quickly inspect it and mark them as either a "reject" (when it contained too many artifacts or bad reconstruction), "wrong orientation" (to flip the object 180deg) or "accept" for correct looking assets.

The manual inspection was surprisingly efficient after we made a tiny fast efficient GUI to flip through the asset bank very fast with simple keybinds. Probably about 3-4h of manual verification work.