Just to let you know, while you have been gone, I've tried several ways to get 3D terrain mesh to show on top of my PR and have had success. I tried what you did, but that does not allow me to include the PR which defeats the whole purpose. If I didn't want to use the PR then I could just place my LC via ADE, but that is not what I want. I'm going to try and explain EXACTLY what I want to do if possible.
OK, I created my PR Scenery, now as everyone knows, PR Scenery is just that SCENERY. It covers the default AutoGen terrain with your own Scenery, none of this is 3D it's just flat detailed texture. That takes care of my first step, covering the ground with my own texture, great, that is now easy to do. Now, here is the problem. Because PR Scenery covers your Autogen with 'flat' texture scenery, you get NO AUTOGEN 3d objects, it's all just texture. You cannot place ADE Land Classes over the area where you have any PR Scenery because it will NOT display. Now, some instructions suggest using a BlendMask, ok, that does only one thing, it allows your default TEXTURE (not AutoGen) to blend through your PR. I don't want that, no, I want to be able to place various ADE LC on top of my newly create PR Scenery (Texture) and have it show as it would as if there was no PR in place, in other words in 3D. Now another suggestion was to use the AutoGen Annotator to place my LC, OK, did that, but......(yes that nasty word again), the Annotator only allows placement of VEGETATION for LCs, it does not add in any buildings or other objects, in other words, if you use a LC such as 'cool crops and town', you will only get the trees and other vegetation, NO BUILDINGS!
That is my dilemma in a nut-shell. I am unable to get any NORMAL ADE LC to show on top of (not through) my PR Scenery. All I can get is either flat texture of the land, or using the Annotator, I can at least get forests and things, but nothing with any buildings. So, I'm left with just placing my vegetation with the Annotator, then by flying over the area in FSX, mark any 'Empty' spots in ADE and just place my OWN objects and buildings to build my own town. This appears to be the one major drawback of using PR Scenery. I have yet to find ANYWHERE on the web, that ANYONE has ever accomplished getting ADE AutoGen LC to actually display over PR Scenery, that is something you have to sacrifice if using PR Scenery. I've tried now for weeks to get it to work, I've tried every suggestion on here and everywhere else, it simply just won't work. It's just the way FSX displays PR Scenery. It always takes precedence over everything else. I have not discovered any way to change this fact. I think I will just use my second option of just placing objects and buildings in specific areas of the LC.
Your conclusions are correct, and confirm what I previously stated regarding what FS2Kx docs and FSDEV forum participants have stated.
By design, ACES 'intended' only visible airport infrastructure objects compiled by BGLComp to display on top of PR or default LC.
But with special grayscale values used in Blendmasks, one "may" be able to get Autogen Annotation to be displayed on top of PR LC.
There is a way to get "G-Poly" objects to display on top of airport infrastructure objects and both default and custom PR LC in FSX.
AFAIK, legacy FS-8 (aka "FS2002"-era) method is still supported through current versions of P3D, and have minimal display anomalies.
The FSX MDL type was modified by ACES as a test of functionality, but disabled use of VTP layering, so anomalies are seen in top-down.
As you discovered, there are complexities involved in using G-Polys, which both ADE-GP and MCX G-Poly Wizard attempt to minimize.
BTW: As we proceed to explore alternate workflows to achieve your current reported goals, we must agree on some scenery terminology.
It is best to reserve use of "Flat" to entirely flat surfaces where terrain mesh has been forced into that shape by CVX vector AB FLX polys.
Although most airports are made 'flat' / "level" to accommodate AI Traffic, you do not use that at this time (me neither ..for
decades).
This must be distinguished from a scenery actually not being 'flat' per se, but it does not have Autogen displayed on it at run time.
CVX Vector AB Polygons assume no Autogen use on airfields, so AFAIK, all such types used via MaskClassMap will not have Autogen.
See: LFT XLS spreadsheet attachment in: 'Making Scenery With SBuilder' tutorial; it lists MaskClassMap textures (all are CVX vector types).
IMHO, we should
not use AB polygons unless we want to exclude Autogen; all other polygons should be specific types from Terrain.Cfg.
I mentioned that the SDK and FSDEV "official' process to display Autogen on custom PR LC at run time is to:
* Use a properly coded Blendmask (this creates a 'digital hole' in the top PR layer) that allows underlying layers to be displayed on top.
...
or:
* Use Autogen Annotator (this creates
*an.AGN files for PR LC tiles, with correct internal complex coding as to world region, season etc.)
I also mentioned attempting to get Autogen from underlying default or custom scenery to show through on top of PR is
unpredictable.
IIUC, no one in the FS Community has an answer as to when / where / why Autogen
does 'sometimes' show through on top of PR.
Thus, I recommend
not attempting to find out how to force underlying default or custom scenery to show through on top of PR.
I am also not aware of a way to copy Autogen Annotation from default LC tiles, custom CVX Vector LC Polygons, or custom PR LC tiles.
They all use
*an.AGN files, but internally there is complex coding as to world region, season etc, that are so involved, few attempt copies.
We are left then, with the challenge of creating custom Autogen Annotation for custom PR LC tiles.
Autogen Annotation for custom PR LC tiles is universally regarded as the worst aspect of FS2Kx scenery creation.
Arno's ScenProc can process aerial imagery and semi-automatically generate rather Autogen accurate to IRL, with default objects.
IMHO, ScenProc has a steep learning curve due to a proprietary scripting user interface.
But, ScenProc has the best available aerial imagery processing engine available for FS2Kx scenery; I hope Arno eventually adapts it for use in MSFS, so that we will have an alternative for the scenery areas in MSFS that Asobo has not yet detailed sufficiently close to IRL.
Alternatively, there are a few obscure Autogen utilities for FS-9 that have a method to port initial work products to FSX and P3D.
These may have their own learning curves and a need to have some in-depth knowledge of both FS-9 and FSX SDK.
You may find that in the amount of time expended climbing their learning curves, it would be quicker to do custom Autogen Annotation.
A discussion of such FS utilities for semi-automatic Autogen creation via a hybrid method involving FS-9 and FSX SDKs is here:
https://www.fsdeveloper.com/forum/threads/autogen-trees-help.43153/post-190405
As stated previously, I do not recommend attempting to use BGLComp to place any 'significantly' large amount of scenery objects.
If you do attempt that, you will incur substantial performance issues at run time on your particular computer configuration.
Frankly, your very large extent of visible airport infrastructure objects compiled by BGLComp over nearly 60 miles is already problematic.
Otherwise, try using "
Forest" to process aerial imagery to achieve BGLComp scenery library object placement more accurate to IRL:
https://www.fsdeveloper.com/forum/forums/forest-fsx-p3d-tree-placement-tool.148/
But rather than have you become even more frustrated, I recommend further study of how to create proper Blendmask source files.
If you have not discerned yet via features built into PhotoShop or other graphics utilities, your linked Blendmask source file was
RGB.
The LFT tutorial was written at a time of transition in the evolution of FSX SDK and SBuilderX, when BMPs showed some limitations.
At that time, the decision was made by ACES and LFT, to begin recommending TIFFs for both Blendmasks and Land-Water Masks.
However, in both such cases, the Channel or stand-alone file type for on/off and gradient masking must be 8-Bit grayscale ...
not RGB.
If you downloaded the updated version of your Blendmask source file in my ZIP I linked you to on March 13, 2025, within:
Agron_Scenery_03-13-2025\Scenery
...you will find a replacement BGL compiled using the TIFF 8-Bit Blendmask with the same grayscale value you had attempted via RGB.
You can also load the updated TIFF 8-Bit version of your Blendmask source file in PhotoShop to see how it is interpreted / referenced.
You must make proper TIFFs before going further down the "Road" with not being able to display underlying default or custom scenery.
Stop and think about it:
Terrain textures (whether default / custom) use masks to display underlying default WC colors / _Hydro attributes.
Custom PR LC 'fades' (Blends !) shorelines into the underlying default WC color and associated _Hydro water attributes with waves, splashing Effects etc. because of successful implementation of
both Blend Masks and Land-Water Masks, so they
do work in FS2Kx.
If that were not working, we would not be able to see any such default or custom "underlying" scenery content.
So, IMHO, it will be best to master the creation of Masks first, before considering other alternatives to the custom PR LC workflow.
That is especially true if you intend to implement custom "alien" landscapes and textures for terrain.
Done properly, you may even be able to utilize underlying Autogen.
GaryGB