• Which the release of FS2020 we see an explosition of activity on the forun and of course we are very happy to see this. But having all questions about FS2020 in one forum becomes a bit messy. So therefore we would like to ask you all to use the following guidelines when posting your questions:

    • Tag FS2020 specific questions with the MSFS2020 tag.
    • Questions about making 3D assets can be posted in the 3D asset design forum. Either post them in the subforum of the modelling tool you use or in the general forum if they are general.
    • Questions about aircraft design can be posted in the Aircraft design forum
    • Questions about airport design can be posted in the FS2020 airport design forum. Once airport development tools have been updated for FS2020 you can post tool speciifc questions in the subforums of those tools as well of course.
    • Questions about terrain design can be posted in the FS2020 terrain design forum.
    • Questions about SimConnect can be posted in the SimConnect forum.

    Any other question that is not specific to an aspect of development or tool can be posted in the General chat forum.

    By following these guidelines we make sure that the forums remain easy to read for everybody and also that the right people can find your post to answer it.

Alternate work-flow for producing this type of complex sloped flatten scenery object (Moved)

Hi Gary, cordial thanks for the great and precious Information you are providing me and the other Aware Reader of this Forum. For me, the Aleutians are a very interessting place, rich of history. A lot of People do not know, that in the Aleutians there was fierce fighting going on during WWII. That must have been a great time flying in Floatplanes or Seaplanes, I'm fascinated about the great Seaplanes build by the Americans, the English, the Germans and the Italians prior to WWII and during WWII.

To be honest, I'm struggling with the combined meshes, I have gone through the Terrain SDK reading and reading it again, I'm frankly getting frustrated again. Somehow I must have mist something pertinent!
I'm trying to find the correct Parameters required for the Resample Tool, because I want to Level the whole thing to Sea-Level as you mentioned above. But anyway, the whole mesh must be reworked, it contains caps and holes.
I really need some hints from you, everything is in the attached file!

I wish you a relaxing end enjoying Weekend!


  • Akutan_Harbor SRTM.rar
    1.8 MB · Views: 203
To depict the combined Elevations Grids, here are some Pictures within Global Mapper:

GM Combined-1.jpg
Hi Conrad:

I have the file linked above, and will take a look at it this weekend. ;)

I will be traveling today, but I hope to get some time before Monday to review all the available data, and will reply here incrementally ...to advise on work-flow(s) for the ~2013 "completed" Akutan Harbor configuration, using:

* TIN CVX vectors compiled by SDK SHP2VEC

* Terrain mesh (TRN gridded vector quads) compiled by SDK SHP2VEC Resample

* A 3D terrain MDL object to cover up terrain grid quad edge aliasing.

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Hi Gary, I need to explain the Problems I'm struggling at the moment a bit more in detail: I'm not struggling with creating a mesh the way it is common. I'm struggling with the special case here with having data which is below sea level. The normal case is well described in tons of materials provided in this forum, the most comprehensive and competent Information and guide-lines are from you for nearly 15 years! I have also watched the very well made instructional Videos from: Rotornut44:

And the following Video, not directly related to mesh creation, but otherwise very useful:

and also a lot of other contributions belonging to Flight Simulation, but also for other purposes. I have seen and consumed so much of information, that the following saying becomes truth: "Nothing but before trees one the forest no more sees".
The Terrain SDK is also not so much of a help, since the examples are kept to a minimum and the cases are just simple ones. What is really missing is a consolidated Guide, a Book for the Scenery Designer based on rich experiences, at least, I'm not aware of any one. Searching through the Information provided here and in other Forums, can become so exhausting, that many times, that I went to sleep in front of the computer! A phenomena by which other persons also have been hit, noticed by me, reading through all the Forums! What I really want to learn is all the different methods which lead to the same or even better results, an optimized method. Lets call this a method-plurality. In the mentioned case here, I could get rid of all the data which is below sea-level, or reduce this to null, easely this way, but you mentioned that it can be done with resample.exe by defining the appropriate Parameters. But the Terrain SDK is here very quiet and invisible about such cases.
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Hi Gary, I found this post on this Forum dating back to 2 Aug 2011 from sfrenchie:

Thanks Gary, excellent input and link.

One must know to say "stop", this is beyond what's fun for me...I have reach that point :)

I am impressed by your knowledge and I'm sure if many of us were to sit by your side for a couple days we would understand what's going on.
On the other end trying to figure it out through posts, links, SDK, etc. can be quite a challenge I don't feel like facing atm.
I'll get back to it at a later time.

What a compliment to you :) While searching through this Forum, I came often across the following sentence: "I am getting crazy....", so I'm not the only one!;) Another sentence I found on another post was: "Alright this is driving me nuts. I bother you guys only when I am really about to commit suicide... :banghead:"
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Hi Conrad:

While I shall require considerable time to prepare an illustrated and explanatory reply to your questions above:

Please review Pages 62 and 53 in this PDF file:

Also, see Page 1 of this PDF file:

...And Page 4 of this PDF file:

NOTE: "MLLW" at Akutan Harbor is 0-AMSL = Sea-Level ...relative to which, FS terrain is (+) as Altitude or (-) as Bathymetric Elevation

Origin of Axes (X,Y,Z Cartesian Coordinates 0,0,0) in Sketchup 3D models are placed on the local terrain horizon in FS.

Akutan Harbor Inner Perimeter road is to be assigned a "Crest Elevation" of 16.0 Feet AMSL on Sketchup's (Z) Axis

Akutan Harbor Breakwater peaks are to be assigned a "Crest Elevation" of 13.0 Feet AMSL on Sketchup's (Z) Axis

FYI: Since a Hydro Polygon effectively conceals any underwater details in FSX, and P3D's submarine may not be able to navigate a shallow 14.5 Foot minimum depth, 3D modeling your Akutan Harbor below sea level ...is at your discretion.

Your imagery-traced vector lines can be used at assigned elevations relative to sea-level, and in Sketchup, intersection of a horizontal Face with the tapered inner harbor at sea-level ("MLLW") can be copied to derive vertices for the Hydro Polygon.

I recommend that this thread focus initially on the intended "completed" configuration of the Akutan Harbor, rather than retaining all Hughes work-in-progress variable elevation data on the inner Harbor floor and in adjacent wetlands outside the perimeter road embankments.

My further incremental replies to elaborate on the actual steps of the work-flow alluded to above will follow "soon".

Please be assured I am quite aware that complexities of FS development are chronically under-documented and/or obfuscated, as well as scattered across many FS websites.

That is part of what compelled my many posts over the years, attempting to share some additonal interpretive info.;)

Sorry, but as my available free time for such replies is rather limited, I cannot predict 'when' more info may be posted.

I hope the above info helps you adapt / convert a 3D model to a CVX vector sloped flatten at 'completed' elevations.

BTW: To keep ones sense of humor intact during challenging development work, perhaps a bit of levity is in order: :laughing:

Remember ..."Its only a model". :alert:

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Hi Gary, once more cordial thanks for the tremendous Information you just provided again, I do not demand a detailled procedure from you, not at all, I just needed some small hints in which direction to go, otherfwise the learning-effect is nil. While searching and reading through this and other Forums, I noticed that sometimes the same People, so called: cheeky monkeys, keep on asking the same question again and again, confirming that they havent learned anything, or they are just too lazy to learn!;) A thousands thanks again for your provided Information and guide-lines above!:) And I'm convinced, that sitting together with you, face-a-face, someone could learn within two hours, more than a year searching through the Internet and watching for hours Videos!:alert:

I just also recognized, due to my improper or inperfect english, that there is much confusion going on between us two. I actually have a lot of small questions and insecurities, but with a great impact, since I don't get my questions through the right way! :alert: Thats why, as an former IT-Professional, I always went to visit my customers directly at their site and on their Computer, because sometimes, even speaking the same language, some misunderstandings and uncertainties were arising!:alert:

I have been searching and reading posts for more than a year on this Forum and other Forums, I have been reading tons of papers, I have watched for many many hours instructional Videos pertaining to Scenery- and Terrain-creation. I have created two sceneries, not perfect ones and not ment for the purists. I have a technical understanding of the processes and techniques involved, one thing I do not have in this is: experience. All my questions in reality are pertaining to experience! But I realize also, that it is difficult (complicated, complex, intricate, tricky) to place questions about experience on an internet-platform, it can never and will never substitute a personal face-a-face talk and explanation!

In ModelConverterX you can create a FlattenBGL, sometimes it is mentioned, that it will create a CVX_something-file. A real CVX-file you can drag onto TmfViewer and you can see the flattens and other structures there. In CvxExtractor you can extract the CVX-structures (Shapes)! But this wont work with a ModelConvererX created FlattenBGL! ModelConvererX created FlattenBGL require also a Texture! So therefor ModelConvererX created FlattenBGL are somehow a Hermaphrodites! In fact, ModelConvererX created FlattenBGL are georeferenced objects! You see, this are all matters of uncertainties, which move me, and a lot of others!
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'Bumped' for edits to my post above. ;) Lets consider this post as closed. Thanks to everyone and especially to Gary for his tremendous amount of Information and knowledge provided! :alert:

In ModelConverterX you can create a FlattenBGL, sometimes it is mentioned, that it will create a CVX_something-file. A real CVX-file you can drag onto TmfViewer and you can see the flattens and other structures there.

In CvxExtractor you can extract the CVX-structures (Shapes)! But this wont work with a ModelConvererX created FlattenBGL!

Please attach an example ModelConvererX created FlattenBGL you cannot decompile in CvxExtractor. :scratchch

ModelConverterX created Flatten BGL require also a Texture!

ModelConverterX created Flatten BGL are geo-referenced objects!


Yes, a CVX vector flatten BGL compiled by SDK SHP2VEC is a TIN used to modify run time display for terrain mesh BGLs compiled by SDK Resample (...from raster elevation source data gridded at regular intervals as TRN quads).


FS terrain ground / Hydro surfaces always require a land or water class texture in order to be visualized by the user aircraft camera at run time.

Default or custom terrain land class / water class textures may be displayed with seasonal attributes depending on GUID types used.

3D objects to cover up terrain as "ground" surfaces with a hardened concrete "Platform" must be textured also, in order to be visualized in FS.

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Hi Gary, that's not a complain or critic on ModelConverterX to make this clear, Arno Gerretsen does an outstanding Job, good heavens, god bless him. What I want to do, is to learn and understand as much as possible, also why is something so and something so. My questions would be more like this: What would you do in this case and what would you do in that case. Why are you doing it this way and etc. I have included all files as Attachement to this post, but I was not able to attach the SketchUp-Project due to its size. Hey Gary, this is not important at all, this is only to expand or enhance my understanding!




  • 7AK Akutan Harbor Flatten.rar
    3.9 MB · Views: 162
Hi Conrad:

I took a quick look at the latter file you attached above.

The question regarding 7AK Akutan Harbor-Flatten-2.BGL is easily answered by clarifying MCX' output options. ;)

After a 3D model (*.DAE) is imported into MCX, it can be exported as a (sloped) flatten via the appropriate menu choice:

MCX Menu > Export Scenery > Save As Type: FSX flatten BGL file (*.BGL)

This would be internally compiled by MCX via SDK SHP2VEC.

This to be distinguished from output of a 3D model as a MDL packaged inside a 'hybrid' BGL along with placement info:

MCX Menu > Export Scenery > Save As Type: FSX BGL file (*.BGL)

This would be internally compiled by MCX via SDK BGLComp

In Sketchup, Export as Google Earth *.KMZ (not *.DAE) ...to retain Geo-referencing of a 3D model imported to MCX. :idea:


The 7AK Akutan Harbor-Flatten-2.BGL file attached above is currently in a MCX ''hybrid" BGL format containing the 3D MDL object along with placement info.

Since it was not output from MCX as a CVX vector flatten BGL, you cannot decompile it using CvxExtractor. :pushpin:

It will be 'placed' at MCX' default geographic coordinates, as no 'custom' placement info will be detected in a imported *.DAE 3D model; otherwise geographic coordinates may have been assigned to it via MCX' Object Placement feature.

BTW: A MCX (or ADE) ''hybrid' BGL output format containing the 3D MDL object along with placement info is 'geo-locked' at the geographic coordinates used for 'placement' inside the BGL.

<?xml version="1.0" encoding="ISO-8859-1"?>
<!-- Created by Scenery Design Engine (SDE) on 12/4/2019 -->


Hope this helps with testing your work-flow options. :)

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