Purpose: To save on disk space taken up by the morphs.
The FaceGen morphs are created as uncompressed *.dsf files in plain text format. This is great if you want to edit the file (assuming you know what you're doing, unlike me). What I've found is, if you're one of those folks that goes overboard creating FaceGen morphs, you end up with a lot of files, taking up a lot of space. My Genesis FaceGen morphs directory alone has 2,571 files, taking up 1.34GB of space. After compression, I still have my 2,571 morph files, but now they just take up 373MB.
My process:
Open the Batch Convert pane: Window->Panes (tabs)->Batch Convert
Click on "Add Directory" or "Add Files" - as desired.
Navigate to the FaceGen morph Directory:
...data\DAZ 3D\Genesis x\Male (or Female)\Morphs\FaceGen
if adding the directory:
Click "Select Folder" - to select the complete directory
or
if adding specific files:
select the specific file(s) and click "open"
You are returned to the Batch Convert pane.
Choose "Compress listed Uncompressed Assets" button
Click the "APPLY" bar to execute.
If for some reason you want to uncompress a file, just use Batch Convert, select the file(s) and choose the "uncompress" option.
Hope this helps.