Ground Elevation

#1
Hi,
I've just about completed this airport, which is the Huntsville International Airport, KHSV. In the image below is a 3D google earth screenshot of the airport:


KHSV.jpg



Notice that the ramp area where the planes park at the terminal is actually above the street level. The elevation of the ramp is 620 feet above MSL and the street level is 608' above MSL. This means the ramp is 12 feet above street level. Also notice the on-ramp that trucks use to go back and forth between the loading stations and the aircrafts. I have this modeled where the ramp is 12' above the lower levels in Sketchup. I have this installed in the P3D simulator and the ramp, terminals, and buildings looks very good. But the problem is that the area where things are 12' below the ramp are covered up and hidden by, which I think is the airport scenery layers in ADE which are flattened, as well as having the Alabama Mega Scenery installed. Usually, airports in ADE are flattened, and I think this is what I'm seeing that has covered the lower levels of my scenery. What do I need to do, or how do I remove this flattened scenery so that it does not cover my scenery in Sketchup?

Ken.
 
#2
in ADE, you need to create a rectangle that removes "Airport Background". Then you have to create your own elevation model using new flattens (with the use individual points option on). Keep in mind that taxiways and runways will always default to the airport elevation.
 
#3
Hi Ken:

A few basic considerations must be kept in mind when modifying a default (aka "stock") airport:

* Use of AI / Ground traffic, ILS approaches in user piloted flights requires Altitudes for all navigable surfaces to be identical

NOTE: This means Airport Properties, RWYs, and CVX vector Flatten Altitudes must be identical (level and ...NOT sloped)


* Use of AI traffic and/or ILS approaches at a modified airport

...and/or:

* Modified Altitudes, RWYs Taxiways or other components / objects in navigable areas that change default FS values

...may also require modification of 'Approach' data in ex: ADE


Airport Background CVX vector polygons, Flattens, and Land Class / Water Class polys textured MAY be sloped in areas where
there will be no use of AI / Ground traffic, ILS approaches in user controlled flights.

[EDITED]

FYI: Airport Background CVX vector polygons, Flattens, and Land Class / Water Class polys textured may be 'segmented', instead of using (1) big CVX vector polygon, provided Altitude and Geographic coordinates of edges are precisely aligned.


Please refer to Jim Vile's excellent tutorial regarding use of segmented CVX vector polygons at airports in this thread:

https://www.fsdeveloper.com/forum/threads/landclass-visibility-problem.15173/


BTW: "Exclude and Replace" (...with a totally new object) is frequently a necessary and desirable work-flow.

And while some may opt to do all editing / create CVX vector polygon content in ADE, one can reduce workload by de-compiling the default CVX vector polygons in:

[FS install path]\Scenery\0302\scenery\cvx2419.bgl

...using Patrick Germain's CvxExtractor and exporting a ESRI *.SHP file.


The resulting *.SHP file(s) may be 'Appended' to SBuilderX, with associated GUID / Altitude values of the original default CVX vector objects intact, then edit KHSV default CVX vector objects and/or create new CVX vector polygon content in:

[FS install path]\Scenery\0302\scenery\cvx2419.bgl

...within SBuilderX.


One may use these "Jump" / "Go To Position" Geographic coordinates for KHSV in SDK TMFViewer / SBuilderX:

Lat: 34.637222

Long: -86.775002


PS: You may wish to note that the default assigned Altitude of Huntsville International Airport, KHSV is actually:

191.719 Meters / 628.9974 Feet AMSL (Meters = "M"; Feet = "F")

...in the airport and CVX vector flatten BGL files.


You may also wish to note that the default Altitude of Huntsville International Airport, KHSV is actually:

192.0 M / 629.9194 F to 194.0 M / 636.481 AMSL ...in the 'navigable' paved airport Apron / Taxiway / RWY areas

...and:

191.0 M / 626.6385 F to 193.0 M / 633.2002 F AMSL ...in 'lower' adjacent paved airport ramps / roadway / parking areas

...within the default terrain mesh BGL file:

[FS install path]\Scenery\0302\scenery\dem0302.bgl


Thus, relative assigned Altitudes must be used for 'flatten' vertex points in custom KHSV Airport Background ground surfaces
to effectively modify the terrain 'shape' in FS at run time.

[END_EDIT]

Altitude values in the FS airport database and Google Earth are both 'approximate', as they are typically based on 90 Meter SRTM and/or GTOPO30 terrain data that 'may' not accurately correlate precisely with real world values.

However, one must either work with the default airport data as it exists in 'stock' BGLs, or make comprehensive modifications to airports and all associated AI / Ground traffic, Approaches, and Terrain objects ...to produce accurate and interdependent components for a fully and functionally compatible result.


GaryGB
 
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#4
Hi Gary,

Thanks for the tutorials. I was able to remove the airport background by creating a poly and using the "Exclude Specific" under Type and "Airport Background Flattens" under Tab. But since I have the Alabama Mega Scenery Earth version 3 installed, this is covering up the lower levels just like the airport background in ADE. So, how do I remove this area so it doesn't cover up the lower levels I created in my model in Sketchup? If I remember correctly, I would use the TMF exe to locate the airport in the Alabama scenery. Is there a quick way to locate this file so that I don't have to go through all of them?

Ken.
 
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#5
in ADE, you need to create a rectangle that removes "Airport Background". Then you have to create your own elevation model using new flattens (with the use individual points option on). Keep in mind that taxiways and runways will always default to the airport elevation.
Hi pinkjr,

Thanks for the tip.

Ken.
 
#6
https://www.fsdeveloper.com/forum/threads/ground-elevation.444517/post-814482

Hi Gary,

Thanks for the tutorials. I was able to remove the airport background by creating a poly and using the "Exclude Specific" under Type and "Airport Background Flattens" under Tab.
That is a good initial procedure; now you can replace it with a 'segmented' Airport Background consisting of multiple derived / modified CVX vector objects and/or create new CVX vector polygon content in SBuilderX using the 'Appended' *.SHP files derived from the original default 1-piece Airport Background polygon content using the SBuilderX Line and Polygon tools.


NOTE: Some of the replacement Airport Background polygons will have a totally level and 'flat' surface; but others (ex: ramps / local airport roads etc.) will have sloped surfaces which are achieved by editing in SBuilderX ...the associated Altitude of individual vertex points that define those polygons.

All those polygons will become (1) -or more replacement Airport Background polygons when 'selected' and compiled to BGL via SBuilderX using SDK SHP2VEC to create the CVX vector polygon BGL(s).

Refer to Jim Vile's tutorial cited above for more details on the process of using multiple Airport Background polygons ...at KHSV.

https://www.fsdeveloper.com/forum/threads/landclass-visibility-problem.15173/


https://www.fsdeveloper.com/forum/threads/ground-elevation.444517/post-814482

But since I have the Alabama Mega Scenery Earth version 3 installed, this is covering up the lower levels just like the airport background in ADE. So, how do I remove this area so it doesn't cover up the lower levels I created in my model in Sketchup? If I remember correctly, I would use the TMF exe to locate the airport in the Alabama scenery. Is there a quick way to locate this file so that I don't have to go through all of them?

Ken.
Please see the recent edits to my initial post above in this thread:

https://www.fsdeveloper.com/forum/threads/ground-elevation.444517/post-814450

Note that the Alabama Mega Scenery Earth product will primarily provide aerial imagery textures that merely drape onto the 'ground' surface defined by the local terrain mesh modification configuration provided by instructions in any 'active' KHSV Airport Background CVX vector polygons with a (level or sloped) "flatten" GUID attribute ...not by CVX vector polygons within the Alabama Mega Scenery Earth product itself. :pushpin:


Note as well that Apron and Taxiway textures may inherit the assigned Altitude of the KHSV Airport itself, and may need to be "Excluded", and are likely the source of the 'ground' surface matching the KHSV airport Altitude, and pbscuring display of your custom bu8ildings / ramps / roads etc. that are at a lower elevation.

Note that Apron and Taxiway textures in your ADE airport file can be 'Excluded', as they will ultimately be replaced by the custom aerial imagery textures superimposed (aka "draped") on top of them by the Alabama Mega Scenery Earth product.

You may, however, need to replace those Apron and Taxiway objects with a 'flatten' CVX vector polygon having a level 'paved' (ex: concrete or asphalt_ surface attribute to achieve the desired terrain shape and assign attributes for AI / Ground Vehicle traffic so that they do not show Ground Roll 'wheel' Effects for dirt / debris.

By 'Excluding' the Apron and Taxiway objects that also would inherit the assigned Altitude of the KHSV Airport, and which, IIUC, ADE implements via de-compilation and copying of those original objects from the default (aka 'stock') KHSV airport file:

[FS install path]\Scenery\0302\scenery\APX24190.bgl

...the Alabama Mega Scenery Earth product aerial imagery textures will then be 'allowed' to drape onto the 'ground' surface defined by the local terrain mesh modification configuration provided by instructions in any 'active' KHSV Airport Background CVX vector polygons ...with no interference by those otherwise underlying / non-displayed SDK BGLComp-compiled airport objects)

GaryGB
 
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#7
Gary

I've been trying to compile my polygon in SBuilderX 3.15 and it keeps saying that I have not selected anything when I have selected it. I'm following the manual to the tee and it's still not doing what it's supposed to do. I've tried clicking on it, using the selections rectangle, and using the selection menu. Not one of them works. I did noticed there are a number of selections where it says "Select Type of Scenery," but these are grayed out., Apparently, one of these have to be selected.

Ken.
 
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#8
Hi Ken:

In SBuilderX' workspace:

* Left-click on the poly-line border or Left-click-hold-drag to draw a selection rectangle around an object to select it.

* An object is 'selected' for ex: BGL compile procedures when its vertex points (aka "vertices") change from Red to Green.


If this does not change the situation and/or you continue to receive a "There is nothing to compile" message, 'Save' a SBuilderX Project file (*.SBP) and 'Export' a SBuilderX Exchange File (*.SBX) and post a link to them here or via PM, and I can try to see what you may be referring to.


FYI: A prior discussion and some links on the above status / error message (if that happens to be what you are seeing):

https://www.fsdeveloper.com/forum/t...scenery-usable-in-sbuilderx.85410/post-239605

GaryGB
 
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#9
Hi Ken:

In SBuilderX' workspace:

* Left-click on the poly-line border or Left-click-hold-drag to draw a selection rectangle around an object to select it.

* An object is 'selected' for ex: BGL compile procedures when its vertex points (aka "vertices") change from Red to Green.


If this does not change the situation and/or you continue to receive a "There is nothing to compile" message, 'Save' a SBuilderX Project file (*.SBP) and 'Export' a SBuilderX Exchange File (*.SBX) and post a link to them here or via PM, and I can try to see what you may be referring to.

GaryGB


Hi Gary,

Yes, the vertices were green, and even though they were green, it still claims I haven't selected anything. I assume you draw the selection rectangle with the Pointer Mode icon that looks like an arrow. After I draw the rectangle and release the mouse click, the rectangle disappears, but they vertices do turn green. They also turned green when I click the border. I exported the file as an .SBX but I don't know how you go about posting a link to it. How do you make it a link?
 
#10
Depending on the size of the *.SBX file, perhaps you could just attach it (and the *.SBP file) ...to a post or PM here.

Otherwise, if using a file storage / download site such as MediaFire, DropBox etc. for a larger file, use the 'chain link' icon to the right of the "T" icon on the forum 'Post Reply' editor icon toolbar ...when composing a reply in this thread or in a PM.

GaryGB
 
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#12
I've tried to attach the .SBP and .SBX files but they do not have the allowed extensions. Even if I send it PM, it still would not allow the upload. Let me see if I can use WinZip to upload it since that is one of the allowed extensions.

Ken.
 
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#13
Hi Gary.

It uploaded this time and both files seem to be attached. I've attached both the .SBP and the .SBX. By the way, the version of SbuilderX I'm using is 3.15, but it still looks like the earlier versions.

Ken.
 

Attachments

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#14
Hi Ken:

The Yellow polygon in your KHSV project (currently defined as "Type - None") must instead have a ex: "LC_Cement - #19" land class type applied to it in SBuilderX; after that is done, you can 'select' that polygon to be compiled. :pushpin:

After you 'select' it, you should be able to successfully compile it to a CVX vector BGL via SBuilderX. ;)


However, in the SBuilderX Polygon tool mode, it might be best for that existing polygon to first be 'broken' into "segments" as:

* (3) smaller polygons: (1) each for the upper and lower areas, and (1) for the sloped Ramp


One must set the Altitude for vertex points of those polygons to elevations that define and distinguish the navigable upper surfaces of the RWYs / Taxiways / Aprons etc. ...from the lower areas.

You can use "variable" individual Altitudes for vertex points in a separately created polygon to create only a sloped Ramp surface descending from the upper level polygon down to the edge of the lower level polygon (along the course of Points 3 to 15 of your Yellow polygon in its current form).

The polygon adjacent to the Ramp polygon for the non-sloped lower level can use a "constant" Altitude for all vertex points, as can the navigable upper surfaces of the RWYs / Taxiways / Aprons etc.

GaryGB
 
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#15
Hi Gary,
Thanks so much for your help. I finally got it compiled. It took me some time to figure out where and how to make these changes.


However, in the SBuilderX Polygon tool mode, it might be best for that existing polygon to first be 'broken' into "segments" as:

* (3) smaller polygons: (1) each for the upper and lower areas, and (1) for the sloped Ramp

One must set the Altitude for vertex points of those polygons to elevations that define and distinguish the navigable upper surfaces of the RWYs / Taxiways / Aprons etc. ...from the lower areas.

You can use "variable" individual Altitudes for vertex points in a separately created polygon to create only a sloped Ramp surface descending from the upper level polygon down to the edge of the lower level polygon (along the course of Points 3 to 15 of your Yellow polygon in its current form).

The polygon adjacent to the Ramp polygon for the non-sloped lower level can use a "constant" Altitude for all vertex points, as can the navigable upper surfaces of the RWYs / Taxiways / Aprons etc.

GaryGB

I'm glad you brought this up because there is something I need to show you that I'm doing in Sketchup that makes for these two levels of elevation. The next 3 Screenshots are my model of the airport from inside P3D flight simulator:


KHSV 1.jpg


This includes the terminals, the Four Points Hotel, and the parking deck across the street.

KHSV 2.jpg


This is the view of the ramp. Notice the Alabama Mega Scenery Earth that is level with the ramp. This is the part I need to get rid of.


KHSV 3.jpg


In this view, you can see that the Alabama surface is covering what's below it.


The next 4 screenshots is my model inside Sketchup:


KHSV 4.jpg



This is the airport model I've created in Sketchup



KHSV 5.jpg


If you look carefully, you can see that the lower ramp goes under the terminal, and of course comes out on the other side. Also notice the sloping ramp that you discussed that is level with the airport ramp and it goes down to the lower level.


KHSV 7.jpg


This is a closer shot



KHSV 8.jpg



The level here is 14 feet below the ramp where aircrafts park. You'll also notice the sloping ramp. What I'm doing is making all the ground terrain inside Sketchup rather than creating polys that would require lining up perfectly with the model in Sketchup. Now that you've seen what I've done and what I'm doing, would you say that all I need to do now is to remove, or somehow exclude the areas where the elevation is lower than the ramp.? Is it okay that I use Sketchup to create the lower levels rather than creating polys in ADE or SbuilderX? If so, the only thing I know to do is finding the file, editing it in Gimp and making those areas either black or transparent so that they don't cover the lower elevations, but I may not be correct doing it that way.

Ken.
 
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#16
https://www.fsdeveloper.com/forum/threads/ground-elevation.444517/post-814600

What I'm doing is making all the ground terrain inside Sketchup rather than creating polys that would require lining up perfectly with the model in Sketchup. Now that you've seen what I've done and what I'm doing, would you say that all I need to do now is to remove, or somehow exclude the areas where the elevation is lower than the ramp.?
Yes.

https://www.fsdeveloper.com/forum/threads/ground-elevation.444517/post-814600

Is it okay that I use Sketchup to create the lower levels rather than creating polys in ADE or SBuilderX?

If so, the only thing I know to do is finding the file, editing it in Gimp and making those areas either black or transparent so that they don't cover the lower elevations, but I may not be correct doing it that way.
Nice looking 3D model ! :)

After now seeing the precision and full 'multi-level' extent of your KHSV 3D model, in Sketchup, it would indeed be more efficient and expeditious to separately 'Group' the lower level ground polygon independently from all other terminal, retention wall and ramp / roadway structures, as well as the upper level structures.

After making that latter Group of objects "Hidden", and with only the specified lower level ground polygon Group "Visible" in the Sketchup work-space, Export that 3D model from Skletchup as a Google Earth *.KMZ file.

In ModelConverterX (aka "MCX"), import the resulting *.KMZ in 'normal' mode (...not using the G-Poly Wizard at this time). :pushpin:

Then click the [Export Scenery] button, and use the option for output of a "FSX flatten BGL file (*.BGL)".

The 'flat' lower level surface of KHSV adjacent to other 3D structures should output as a custom sloped CVX vector airport background flatten BGL.

http://www.scenerydesign.org/2013/04/flattens-from-3d-objects/


Set FS display of terrain mesh complexity to 100%, and FS terrain resolution to 1 Meter when you test that BGL in FS.

We may then see if MCX can assign precise placement for these objects with such a close proximity when rendered in FS. ;)


PS: If that custom sloped flatten still does not display the lower level ground draped with Alabama Mega Scenery Earth imagery, there is probably a local terrain polygon (ex: Airport Background CVX vector type or other BGLComp XML type airport infrastructure) that still needs to be excluded properly.


GaryGB
 
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#17
After making that latter Group of objects "Hidden", and with only the specified lower level ground polygon Group "Visible" in the Sketchup work-space, Export that 3D model from Skletchup as a Google Earth *.KMZ file.

In ModelConverterX (aka "MCX"), import the resulting *.KMZ in 'normal' mode (...not using the G-Poly Wizard). :pushpin:

Then click the [Export Scenery] button, and use the option for output of a "FSX flatten BGL file (*.BGL)".

The 'flat' lower level surface of KHSV adjacent to other 3D structures should ouput as a custom sloped CVX vector airport background flatten BGL.

http://www.scenerydesign.org/2013/04/flattens-from-3d-objects/


Set FS display of terrain mesh complexity to 100%, and FS terrain resolution to 1 Meter when you test that BGL in FS.

We may then see if MCX can assign precise placement for these objects with such a close proximity when rendered in FS. ;)


PS: If that custom sloped flatten still does not display the lower level ground draped with Alabama Mega Scenery Earth imagery, there is probably a local terrain polygon (ex: Airport Background type) that still needs to be excluded properly.


GaryGB

Hi Gary,

I assume before I do this, I would get rid of the Alabama terrain that's covering that lower section. Is it possible to make that area transparent so that it doesn't show in the sim and cover up the lower areas? I would like to do this without having to remove the file, which will also remove some of the land areas around the airport. I've located the file using the TMF.exe and the file name is AL_2017_62.bgl. Here's a screenshot of the file:


KHSV TMF File.jpg




At one time, I needed to shorten the runway in the Alabama scenery at the Birmingham Airport and it seems that you posted some information about how to do that but I could be wrong. For some reason, I don't see a way to do anything with this file. I don't see anyway to convert this file into a photo file, other than taken the screenshot, and edit it in Gimp. Another problem is that the resolution is crappy and it's hard to distinguish exactly where I need to edit it. I tried to upload the AL_2017_bgl file but it keeps saying that the file is too large. I even compressed it in WinZip and still says it's too large. I'm not sure the maximum size allowed here but the original file size is 40 Mb. I can't see why this file should be a problem to upload. If you know, could you explain to me the proper procedure to edit the file in Gimp? I mean, that's the only way I know that one could make changes in this scenery. I remember you posted instructions in another thread but I don't remember the category nor the thread name.

Ken.
 
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#18
Hi Ken:

There should be no need to post a link to- or to modify- "AL_2017_62.bgl" at this time, as it is only a custom photo-real imagery BGL that drapes onto whatever ground surface is on the top layer of the FS terrain.

It is extremely unlikely that "AL_2017_62.bgl"custom photo-real imagery is not causing the the ground surface which obscures the view of the intended lower level of the airport area in question.

That ground surface on the top layer of the FS terrain 'could' include Airport Background 'flattens', RWYs, Taxiways, Taxiway paths, Aprons etc., since they will normally all be set at the same (higher) Altitude of the navigable (upper) surfaces of the airport, and may require modification / exclusion in any areas that 'overlap' the intended (lower) area of KHSV airport under discussion in this thread.

If you have made a copy of the default KHSV airport with any modifications whatsoever, attach or link to a *.ZIP archive of that ADE *.AD4 project file, and any BGLs compiled by ADE from that *.AD4 project file.

If you also ZIP and attach- or link to- a Sketchup *.KMZ export of your KHSV airport 3D model, I will take a look at what may be required to put your 3D model into position and eliminate the ground surface which obscures the view of the intended lower level of the airport area in question.

GaryGB
 
#19
Ken I think you are still confused by photoscenery. Disable it in the scenery library and you will see the default terrain is still there. It covers nothing up by itself. Drapes on the terrain as Gary says. You just need to tell P3D to make the terrain lower at that point.

As a quick simple test, draw a polygon in sbuilder around that area, make it a flatten with the lower alt you want. Test in sim. If it is still not flattening, you have an airport flatten overiding it still.

Once you confirm flattening is working in that area, you can do a neater flatten with the flattens from 3d objects link form Gary above.

And thanks Gary. I never knew about that one.
 
#20
https://www.fsdeveloper.com/forum/threads/ground-elevation.444517/post-814746

Ken I think you are still confused by photoscenery. Disable it in the scenery library and you will see the default terrain is still there. It covers nothing up by itself. Drapes on the terrain as Gary says. You just need to tell P3D to make the terrain lower at that point.

As a quick simple test, draw a polygon in sbuilder around that area, make it a flatten with the lower alt you want. Test in sim. If it is still not flattening, you have an airport flatten overiding it still.

Once you confirm flattening is working in that area, you can do a neater flatten with the flattens from 3d objects link form Gary above.

And thanks Gary. I never knew about that one.
Many thanks are due to Arno for implementing the option for output of a "FSX flatten BGL file (*.BGL)" from a 3D model via MCX ! :wizard:

GaryGB
 
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