Why is there no ply file in some scenarios' files

According to the dataset downloaded from the code, there are 5 files in the folder of the scene, but some are missing the.ply file

Start with the code that downloads the dataset and inspect how scene folders and their files are selected. Compare scenarios that include a .ply file with those that do not, then establish whether the missing file is expected; done means the behavior is explained or corrected and covered by an appropriate check.

Written by the indexing model from the issue text.