• 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.

Correct a part of a road

Hi everybody

I create an airport scenery where there is a misplaced part of a road. I would like to replace it correctly

To do that,
- I create a new part of the road at the good place (with IS3).
- With ADE, I drew a specific exclude poly on the wrong part of the road.
It work, but it delete the entire road.

Is there a way to delete only a part of a road on FSX, P3D ?

Thank for your help :)

CVX vector excludes used as a specific type of exclude (ex: a tiny triangle that touches / overlaps an object anywhere along its extent) will still cause the portion of a vector line or polygon to exclude that is within the local QMID-11 (LOD-9) quad area to be fully excluded.

One must replace that the excluded portion of a vector line or polygon that is within the local QMID-11 (LOD-9) quad area with a 'corrected' object.

Hope this helps ! :)

Ok, it's a little difficult but if I understand.
In my case, for a road, if I exclude a part of it, all the portion will be excluded.
And I must redraw the road entirely
Indeed; for 'most' CVX vector objects, the "clipping" boundaries are a QMID-11 (LOD-9) quad area.

In FS9, it was a much bigger QMID-7 (LOD-5) quad area in which we would have to replace excluded objects (until we discovered ways to 'edit' them).

Which brings us to IMHO, the "easier" way to correct or otherwise modify CVX vector objects. :idea:

A general overview of the workflow would be:

Make a backup archived ZIP of the CVX vector BGL containing the road to be changed.

De-compile the original BGL in question in Patrick Germain's CvxExtractor GUI, and output to (multiple) ESRI SHP files

Append (all) those ESRI SHP files to SBuilderX version 3.15

Edit the road vector object as desired; export a SBX project data exchange file as a backup for future use.

Select the entire set of objects in the SBuilderX work-space, and compile to (1 or more) CVX vector BGL(s).

In FS, use the edited BGL(s) output by SBuilderX instead of the (1) original CVX vector BGL containing the road to be changed.


CAVEAT: For scenery distributed to the public, IMHO, it is best to only "Exclude and Replace" with separate BGLs, and not to edit- then distribute- those edited copies of original BGLs.

Thus, in that type of distribution scenario, a 'replacement' BGL may contain only the replacements for the objects that were 'excluded', and the original CVX vector BGL is still required to be kept 'active' in the scenery library GUI stack of Area layers.


Hope this helps you explore your options for changing a road object. :)

Last edited:
Hi again:

Post the Geographic coordinates for the road section in question in a reply here. ;)

Alternatively, in a FS flight session: :idea:

1.) Set user aircraft camera view mode to "Top-Down"

2.) Hold down <Ctrl> key, then tap the <Spacebar> key (to point aircraft to North)

3.) Slew your user aircraft into position over the center of the road section you wish to change

4.) Create a "saved flight" (aka "*.FLT" file)

To save a flight:

FSX Menu > Flights > Save...

Fill in flight Title and Description fields, then click {OK} button

You should now have a saved flight in:

C:\Users\[user name]\Documents\Flight Simulator Files\

Attach a ZIP file of (only) the *.FLT file to a reply in this thread, so I can better explain how to ID the BGL(s). :pushpin:

Hi again:

The Decimal Geographic coordinates are:

Lat: 43.207813888888888888888888888889

Lon: 6.4814583333333333333333333333333

That is La Môle – Saint-Tropez Airport: ICAO LFTZ


Click on "Coordinates" at the top right of the above linked wiki page; on the next page, click link to Google Earth (Desktop Edition) or Google Maps (Satellite)

This shows southern France; we now identify that location in the FS Terrain SDK Base File diagram:


That shows the area of interest as being in FS Scenery Area "0602"

Browse to [FSX install path]\Scenery\0602\scenery\dem0602.bgl and open it in SDK TMFViewer

TMFViewer Menu > Jump > Lat Long... > Latitude: 43.207813888888888888888888888889, Longitude: 6.4814583333333333333333333333333; click [OK]

TMFViewer Menu > View > QMID grid > QMID-11

Zoom in to QMID-11 grid extent with NumPad <+> key

Hover Mouse within the local QMID-11 grid extent and read the parameters on the status bar at the bottom of the TMFViewer window: "File# 4916"

TMFViewer Menu > File > Open > Browse to / Select / double-click on: [FSX install path]\Scenery\0602\scenery\cvx4916.bgl

Right-click on the Red vector poly-line; "Identify vector features" lists GUID(s) for that road segment: {325DD470-B342-4D15-AC54-F67ED9F5914F}

Correlate this with FSX Terrain SDK "Vector Shape Properties GUIDs"


Roads_Asphalt_2_Lanes_Undivided_Median {325DD470-B342-4D15-AC54-F67ED9F5914F}

This will be the road to locate and edit when a de-compiled (copy) of the default CVX vector BGL is "Appended" to SBuilderX

De-compile a copy of [FSX install path]\Scenery\0602\scenery\cvx4916.bgl using Patrick Germain's CvxExtractor GUI to output ESRI SHAPE file(s)



In SBuilderX version 3.15 (64-bit):

SBuilderX Menu > File > Append < "SBuilderX - Appending a Polygon Shape file" dialog opens >

In "SBuilderX - Appending a Polygon Shape file" dialog:

Under "Name or Label of Imported Polys" > "Get from this field" pick-list, choose GUID

Under "GUID of Imported Polys" > "Click to set the GUID (or type" > "Get from this field" pick-list, choose GUID

Append all ESRI Shape (aka "*.SHP") files output by CvxExtractor when it de-compiled [FSX install path]\Scenery\0602\scenery\cvx4916.bgl

NOTE: See SBuilderX Menu > Help > SBuilderX Help for info on using line mode editing functions


If this project is intended for personal use only, and not for public distribution, use the following work-flow; public distribution requires a different work-flow.

When finished editing the road (ex: over a real-world "background map" from one of the online web tile servers such as Google Maps API Satellite):

Zoom out until all Appended vector objects are visible, then drag a selection rectangle around them all so they are "highlighted"

SBuilderX Menu > File > BGL Compile > 'check' to select "Terrain Vector"; click [Compile] button

Make an archived backup copy of [FSX install path]\Scenery\0602\scenery\cvx4916.bgl inside a ZIP file; delete the original cvx4916.bgl file

Move those BGL file(s) output by SBuilderX into: [FSX install path]\Scenery\0602\scenery\

Use those CVX vector BGL(s) output by SBuilderX instead of the above [FSX install path]\Scenery\0602\scenery\cvx4916.bgl

I hope this general procedural guide helps you achieve your project goals. :)

Last edited:
Hi Gary
It work. There is the correct road in FSX.
But I don't understand one thing : The size of the new cvx file is only 1Ko. The original was 2890Ko .... !

EDIt : I forgot to select all lines and polys before compil. I think it's my mistake

You say this method is for personal use only. Why ? And What is the other way ?
Last edited:
Hi Luc:

For a scenery distributed to the public, it is IMHO, best not to 'substitute' default BGLs with 'custom' BGLs, and instead to Exclude and Replace ...if possible. :pushpin:

To Exclude a CVX vector object (ex: a road), one creates 1 or more small triangular polygon that overlapa a road poly-line within a QMID-11 to be 'changed'.

The GUID for the CVX vector Exclude triangular polygon(s) must be specific to the CVX vector object 'type' that one wishes to exclude.

For example, in SBuilderX work-space, 'select' a polygon > right-click > 'properties' > {Vector Polys} tab > pick-list, choose: "Exclude_All_Roads" (Type-6)

When the BGL containing that CVX vector Exclude specific to the CVX vector object type that one wishes to exclude is loaded from a FS Scenery Library GUI Area layer position higher in the priority 'stack of Area layers', the result will be that the 'Excluded' object will not be rendered by FS at run time.

One will compile the edited 'Replacement' CVX vector road object into a separate BGL that loads from a FS Scenery Library GUI Area layer position higher in the priority 'stack of Area layers' than that of the Area layer that contains the BGL for the 'original' CVX vector road object.

When the BGL containing that 'Replacement' CVX vector road object loads, the 'Replacement' object will be rendered by FS at run time.

If you require a more detailed explanation of the steps involved in this latter process to Exclude and Replace the CVX vector road object for this project area using ex: SBuilderX, feel free to inquire further, and I shall try to find some additional free time to expand this mini-tutorial to include that procedure. :)

Last edited:
A little difficult to understand. :oops:
I look better tomorrow.

Maybe a solution quite easy, is to create an exclude (like in my first post) with ADE (for example) to remove the wrong part of the road (and therefore the entire road).
I this way, the default bgl are not deleted. There is only a bgl in the "scenery" folder of the scenery ...
and add a new road, correct, with IS3 (or other).
But maybe there are some inconveniences to this method, I don't know ... What do u think about that ?
Last edited:
If you already have an Exclude BGL for the road that is working properly within the local QMID-11 quad, you can certainly use that one. :)

Then create the Replacement road in SBuilderX by editing a 'Appended' copy of the ESRI SHP file output by Patrick Germain's CvxExtractor GUI: RDX4916.shp

In SBuilderX work-space, with a QMID-11 grid and a aerial imagery background 'Map' displayed on screen for the area adjacent to LFTZ

...by left-clicking to select the segments of that Appended poly-line vector object, then right-clicking it, you can:

* change the width to ex: 10 Pixels wide

* drag it into alignment with the real world road over an aerial imagery background using images from either of several web tile servers

* add or delete segments

* otherwise modify the road width or vector type GUID elsewhere along its course within the local QMID-11 needing to be replaced etc..

When the Appended poly-line vector object road has been edited to your satisfaction:

* select ONLY those road object segments within the local QMID-11 adjacent to LFTZ, and compile it to a BGL.

Note that ADE does not work with 'all' CVX vector road attribute types, whereas AFAIK, SBuilderX does.

Also, SBuilderX allows for the easier use of a continuously zoom-able / pan-able aerial imagery background ...which is some of the reasons I suggested SBuilderX rather than ADE to change your road. ;)

Last edited: