You may alternatively extract (or compress) GTR and many other files with
3DSimED.
Please accept my apology for my previous "Shorthand" answer to your question; I hope that this is a more "precise" explanation. I am not a paid spokesman for
3DSimED3 but I AM a staunch advocate of purchasing software that makes daunting projects considerably easier for non-professionals like myself who simply wish to create or customize simulated objects. Inexpensive programs such as
3DSimED,
ZModeler and
BobsTrackBuilder have made it possible for me to create and/or modify objects from
Grand Prix Legends, NASCAR Racing, MS Flight Simulator, rFactor (1&2), Grid, F1 20xx, Forza, ALL of the
Simbin titles, etc.. Once the idiosyncrasies of these apps are mastered, they ARE the easier way to modify many objects. I am as pleased to contribute to brilliant programmers such as Dave Noonan, Oleg and Brandon as I am to the major game providers.
The following screen captures may best illustrate my methodology:
STEP 1 - Click "Expand>GTR:
STEP 2 - Create new folder:
STEP 3 - Click "Import> Select Import Filename":
STEP 4 - Right-Click on object, then click "Material"> "mirror" from drop-down list:
STEP 5 - Click (seventh button from left) "Edit Channel Texture Coordinates"> "Scale UV"> Scale/Offset UV Channel 0":
STEP 6 - Change text in "Scale U" box to "-1.000", click green check-mark, then "Export" > "
GTR2" > "Save Model Data", and click on "Export Textures".