[Casimiro Notevi]

Hace años que no uso esto, pero en la documentación pone lo siguiente:

How to Use and Store Relative Paths

1) Set the AddOptions to AddRecurseDirs and AddDirNames:

Código Delphi [-]
with ZipMaster1 do
AddOptions := AddOptions + [AddRecurseDirs, AddDirNames];

2) Add a file specification like *.* or *.pas or something like this:

Código Delphi [-]
ZipMaster1.FSpecArgs.Append( '*.*' );

3) Set the RootDir property to the desired base directory, Drive and Directory where the relative path should start.

Código Delphi [-]
ZipMaster1.RootDir :='C:\aBaseDir\AnotherBaseDir';

4) Now do an Add, and you should have the desired result. The Drive ID and Dirname of your base directory will not be stored in the archive.

Código Delphi [-]
ZipMaster1.Add;

NOTE: The reason that demo1 saves whole pathnames is because it's GUI design intentionally stores complete pathnames in the FSpecArgs.