First: please leave the existing loot-110K-4tiles, loot-150K-4tiles and Ulli1M samples in place and do not change them.
They have been used for various papers and it is a good idea to keep them.
Let's presume we want to create a dataset of loot, compressed at various levels of detail.
Get a copy of the original 8i loot ply files, and put it in a folder loot next to the toplevel cwipc_test folder. The original 8i datasets can be found at https://jpeg.org/plenodb/pc/8ilabs/.
First we need to determine the parameters for converting loot to our coordinate system and scale:
cwipc_view --filter analyze --playback ../../loot
Let it run for a bit (you won't see anything because loot is going to be very big), then press quit. You will get a suggested transform. Modify to your needs, and inspect the result:
cwipc_view --filter 'transform(-200,0,-300,0.0018)' --playback ../../loot
If that looks good create your output
cwipc_grab --filter 'transform(-200,0,-300,0.0018)' --playback ../../loot --compress --compress_param octree_bits=6 loot-compressed/depth6/
Check the results (note that frame rate is lost, currently):
cwipc_view --playback loot-compressed/depth6
Now repeat for other parameters.