Missing file in 3DJCG repo

Thanks for publishing your work! I'm trying to train 3DJCG using your other repo and couldn't find how to generate the "_aligned_single_obj_idx.npy" file - 
https://github.com/3dlg-hcvc/3DJCG/blob/34b62fb8b9b47d61685c318112f35e01c683fa99/lib/joint/dataset.py#L392
Could you please help?

