Hello:
Your GP looks good !
FYI: P3D 'currently' supports display of legacy FS2Kx SCASM / ASM code,
BGLC-compiled non-MDL based Ground Polygons (aka "G-Polys / GP's") which do not allow for use of Specular or certain other Material Property attributes on those 'flat' 3D models.
Reportedly P3D support for display of legacy
non-MDL based G-Polys will (eventually) end.
The alternative is to create native P3D-compliant
MDL-based GP P3D version 2.x or later SDK
XtoMDL-compiled (and
not compiled via the FSX SDK or P3Dv1.4x SDK
XtoMDL, that is essentially identical to FSX SP2 / ESP, and which produces 'flat' 3D
MDLs that can
not utilize Z-Bias Material Properties)- in order for a "negative" Z-Bias Material Property to be implemented and displayed at run time.
P3D version 2.x or later SDK-compliant
MDL-based GP's
do allow Specular / other Material Property attributes on 'flat' 3D MDLs.
Unfortunately, the methods utilized in more current (post-ADEv1.70 ?) versions ADE GP Editor Tool which, IMHO, is apparently well-intended in an effort at "making things simple", reportedly may not allow end users to discern via its GUI, just exactly what type of GP they are actually creating when they are working in "P3D mode".
AFAIK, this may make it necessary for some end users to import compiled BGLs containing their GPs into MCX to see whether they utilize "negative" Z-Bias, and whether those layers are using a 'staggered' layering scheme, wherein such layers are separated by an interposed group of 3 empty /
un-assigned layers, so that
assigned GP layers appear on
ex: every 4th layer between
ex: 16 and 32 (to show SimObject Shadows.)
Hope this helps clarify challenges end users described recently with (post-ADE_v1.70 ?) versions ADE GP Editor Tool.
GaryGB