Hi Ken:
The thread you cited above is here:
http://www.fsdeveloper.com/forum/threads/editing-ground-textures-for-updated-airport-scenery.441812/
PS: If you plan to publicly distribute your scenery modifications for use by anyone else, you should
NOT edit default FS files, but instead learn how to "Exclude and Replace" default scenery content with custom content, as this would require end users to use
your edited *.AGN files.
This can be done using "Exclude" BGLs, and custom photo-real aerial imagery land class BGLs that incorporate Blend Masks when compiled.
These BGLs can be placed in a "active" Area layer above the default or 3rd party BGLs to be 'modified' by your custom BGLs that modify- / substitute for- display of the default scenery.
If you only want to edit the Autogen for a default scenery land class area, you can "Exclude" the default Autogen with custom "Exclude Rectangles" that specifically target Autogen objects.
These "Exclude Rectangle" BGLs can be created and output to a BGLComp XML-type BGL via AFX or ADE etc..
Alternatively, a custom photo-real aerial imagery land class BGL can be used that incorporates a Blend Mask when compiled.
The Blend Mask can control where you will see:
* default land class textures with their associated default Autogen annotations
...and where you will instead see:
* custom photo-real aerial imagery with any associated custom Autogen annotations
...within the Geographic extent of coverage for your project BGL.
NOTE: Custom Autogen annotations that "Replace" the default 'Excluded' Autogen annotations will be placed onto the 'new' custom photo-real aerial imagery land class texture (which can either have a visible aerial image ...
or be a purely 'transparent' surface layer with NO visible aerial image if desired).
GaryGB