Secret Doors?

[Cranky Old Man]

compound_3 is not the name of the decals, its actually different decals that have been grouped together which names thrm to compound so in this case its the 3rd compound. To group objects you choose all the items you want to group and then press B on the keyboard

Yes, I know. That's why I wrote
Tracks in front of it are made by a group of what may be decals, named "Compound_3".
instead of:
Tracks in front of it are made by several "Compound_3" decals.