Hello:
1.)
In SBuilderX:
a.)
Load the above project back into SBuilderX from its
*.SBP project file
b.)
Select the polygon you mapped with LC_Dirt texture <
SBuilderX polygon vertices are shown highlighted in Green >
c.)
Right-click one of that selected polygon objects vertices or poly-lines <
context menu pops up >
d.) In the context menu pop-up, choose
Properties < SBuilderX Polygon Properties dialog opens >
e.) In SBuilderX Polygon Properties dialog, click on [
Vector Polys ] tab
f.) Scroll in GUID pick-list and
select Type 121: LC_DIRT
g.) With
Type 121 - LC_DIRT selected, click the [
Info] button above the GUID pick-list <
Description from FSX / Terrain.Cfg pops up >
h.) Note that "
Textures = DIRT" is listed in that
SBuilderX pop-up message box
2.)
Browse to: [
P3D install path]\Texture sub-folder (
...this info is based on the FSX folder structures; change paths as needed for P3Dv4.x 
)
a.)
Copy <Ctrl+C> the FSX
default (legacy format) texture otherwise used by
default P3D for LC_DIRT ...into the Windows clipboard:
[
P3D install path]\Texture\dirt.r8
b.)
Paste <Ctrl+V< from the clipboard, the texture mapped to your polygon object ...to your SBuilderX output scenery project
\Texture folder
NOTE: The target
\Texture sub-folder must be 'paired'
with a
\Scenery folder containing the
CVX vector polygon BGL compiled by
SBuilderX
SBuilderX' output scenery project
\Texture folder and
\Scenery folder must be nested under a top folder
ex: named for the project ICAO etc.
3.)
In P3D Scenery Library GUI: (
This is the legacy procedure of adding custom scenery; LM prefers use of "Addon XML" methods now !
)
a.) Create a new layer for your scenery project folder chain via "[
Add Area]" button
b.) Be certain to
position your scenery project in the FSX Scenery Library GUI stack of Area layers ...
above any layers for
FTX OpenLC
FYI: By default,
FTX Central utility alway re-inserts
FTX layers to a position at- / near the top of-
P3D Scenery Library GUI stack of layers.
In addition to substituting 'custom' texture images for P3D 'default' texture images (under their
same original file name) that will be used to map onto custom CVX Land Class objects, your OrbX FTX OpenLC scenery package may add custom entries to the 'active'
Terrain.Cfg which need to be retained by that file in order for those scenery region packages to be able to display the FTX custom scenery as intended by the developers.
By default, in the
FTX Central configuration utility which is run automatically following installation of the above cited OrbX FTX scenery packages, when activating the
ex: OrbX FTX "
North America" mode:
* Custom entries are added to the 'active'
Terrain.Cfg if they are not already present.
* Several OrbX FTX scenery Area layers are added to the 'top' position of the 'active' FS
Scenery Library GUI stack of layers.
BTW: When SBuilderX substitutes the "
Modified Terrain.Cfg", existing custom OrbX FTX entries are no longer in the 'active' copy of Terrain.Cfg if the Orbx FTX entries already in that file are more recent than what is provided by the Terrain.Cfg installed by SBuilderX (which AFAIK has not been updated since it was released by Richard Ludowise and Luis Feliz-Tirado in November 2006).
Manually running OrbX
FTX Central utility and toggling between "
default FSX" and "
North America" mode restores the proprietary custom entries to the 'active'
Terrain.Cfg.
IIRC, this should leave the existing content of the "
Modified Terrain.Cfg" intact aside from a few minor "
RenderPriority" value changes generally regarded by the FS development community as compatible with both default and custom scenery display.
IMHO, one might remedy this by installing "
Modified Terrain.Cfg", then immediately afterwards, manually run OrbX
FTX Central utility.
PS: Because by default, OrbX FTX scenery Area layers are added to the 'top' position of the
P3D Scenery Library GUI, custom scenery may not render properly (if at all), so one should allow for non-OrbX add-on or personally-created custom scenery to be loaded
later by placing them
above the OrbX FTX scenery Area layers ...at- or nearer to- the '
top' position of the FS Scenery Library GUI.
However, each time OrbX
FTX Central utility is run and one activates the OrbX FTX "
North America" mode, OrbX FTX scenery Area layers are again automatically added to the 'top' position of the 'active' FS
Scenery Library GUI stack of layers by default.
One can change that default behavior of OrbX FTX Central utility by configuring the OrbX FTX scenery Area layers to be automatically placed at a
lower position in the 'active' FS
Scenery Library GUI stack of layers by:
OrbX FTX Central Menu > Tools > Scenery Library Configuration >
FTX Scenery Library Insertion Points
NOTE: Newer versions of OrbX
FTX Central utility may be subject to a different menu / dialog configurations
This results in an assigned position, above which, the OrbX FTX scenery Area layers will 'never' be inserted ...until a new
Insertion Point is assigned within that
FTX Central utility dialog.
Hope this info helps with the learning process.
GaryGB