What is FSX terrain mesh and how do I set it up?

Terrain mesh in FSX and FSX: Steam Edition is elevation data that shapes mountains, valleys and ground contours. Install it as an activated scenery area containing mesh BGL files, then set Mesh Resolution to the package’s detail level and keep global mesh below local airports and scenery in the Scenery Library.

What does terrain mesh change in FSX?

A terrain mesh replaces or supplements FSX’s default elevation grid, giving the simulator more accurate hills, ridges, valleys and mountain profiles. The advertised resolution, such as 38 metres or 19 metres, describes the approximate horizontal spacing of elevation samples; it is not vertical accuracy.

Mesh does not sharpen ground textures, add autogen or move coastlines. If those are the improvements you want, installing a higher-resolution elevation mesh will not solve the problem. Our guide to mesh coverage, resolution and package selection explains how global and regional products differ.

How do I install terrain mesh in FSX?

The safest installation method is to give each mesh package its own folder and activate that folder through the FSX Scenery Library.

1. Extract the download outside FSX first. Read its included instructions because some packages divide the data into separate regional areas or supply airport elevation corrections.
2. Check the folder structure. A typical package has a root folder containing a scenery subfolder, with the mesh .bgl files inside it: Addon Scenery\My Mesh\scenery. A texture folder is usually unnecessary for elevation-only mesh. Our FSX scenery folder and library walkthrough covers the standard structure in more detail.
3. Move the package to a permanent location. This can be inside Addon Scenery or in another stable folder. Do not leave it in Downloads, a temporary extraction directory or a removable drive.
4. Open the Scenery Library. Start FSX, open Settings > Scenery Library, choose Add Area, and select the package root that directly contains the scenery subfolder. Do not select the BGL files individually.
5. Work around the old folder-picker problem if necessary. On some Windows installations, the dialogue opens the selected folder instead of accepting it. When that happens, click the blank area of the folder pane and confirm again.
6. Activate every required region. Large packages may require one Scenery Library entry per continent or region. The installation notes for the multi-region FreeMeshX package provide a practical example of this arrangement.
7. Confirm and let FSX rebuild its scenery index. Make sure the new entry is enabled, close the settings dialogue and restart FSX if the change is not visible immediately.

Copying mesh BGL files directly into the shared Addon Scenery\scenery folder can work because that area is normally active, but we discourage it. A dedicated folder makes conflicts, updates and removal much easier to manage.

Standard FSX mesh BGLs generally work in FSX: Steam Edition as well. The usual problem is an older installer writing to a boxed-FSX directory, so verify that the files were placed in a folder used by the edition you actually launch.

Which FSX mesh settings should I use?

Set Mesh Resolution to the package’s stated resolution, or to a finer value if you use several meshes with different detail levels.

For example, a mesh advertised at 19 metres needs a Mesh Resolution setting of 19 metres or finer. Selecting a finer value does not manufacture extra detail from that dataset; it only permits FSX to use finer mesh where one is available.

Where should mesh sit in the Scenery Library?

Broad regional or global mesh should sit low among your add-ons, below airports and detailed local scenery but above the stock terrain entries. Local airport packages often contain flattens or elevation corrections that need to take precedence.

FSX normally selects the highest-resolution mesh available at a location, so a detailed local mesh can supersede a coarser global one. Library order still matters when packages overlap at similar detail levels or include correction files, so follow any package-specific layering instructions.

Why does installed terrain mesh not appear?

Invisible mesh is usually caused by an inactive scenery area, the wrong folder level or a Mesh Resolution setting that is too coarse.

• Incorrect folder selected: the activated root must directly contain the scenery folder. Extra nested package folders are a common extraction mistake.
• Files installed into the wrong FSX edition: check the active Scenery Library rather than assuming a boxed-FSX or Steam installation path.
• Region not enabled: multi-part packages may create separate entries, each with its own enabled checkbox.
• Resolution set too low: choose the package’s stated metre value or a finer setting.
• Testing in unsuitable terrain: flat areas may show little difference. Compare a known mountain ridge or valley inside the package’s documented coverage.
• Another mesh is more detailed: FSX may be displaying a higher-resolution local dataset instead of the newly installed global mesh.

Why are airports on plateaus or in trenches?

Airport plateaus and trenches occur when improved surrounding terrain exposes a mismatch between the mesh and FSX’s fixed airport elevation or flatten. Keep the airport scenery above the broad-area mesh and install any elevation-correction files supplied with the package.

If the problem began after enabling one mesh region, disable that entry temporarily to confirm the cause. Do not delete random BGL files: correction files may cover many airports, and their purpose is rarely clear from the filename alone.

Why are coastlines or water still wrong?

Terrain mesh cannot reposition FSX coastlines, lakes or rivers because those features come from vector scenery. A better mesh can even make an existing shoreline mismatch more obvious, such as water climbing a slope or a visible gap between the coast and terrain.

Does higher-resolution mesh reduce FSX performance?

Higher-resolution mesh usually affects terrain loading and stuttering more than steady frame rate, although the result depends on coverage, storage speed and FSX settings. Global packages also require substantial disk space because they cover many regions.

If performance worsens, reduce Level of Detail Radius first, then lower Mesh Complexity or choose a coarser Mesh Resolution. Change one setting at a time so you can identify which adjustment helped.

How do I remove FSX terrain mesh safely?

Remove or disable the mesh through the Scenery Library before deleting its files.

1. Disable the scenery entry and test FSX if you are diagnosing a conflict.
2. Remove the entry from the Scenery Library once you are certain it is no longer needed.
3. Exit FSX and delete its dedicated folder. Restart the simulator so it can rebuild the scenery index.

Deleting an active folder first can leave a broken path in scenery.cfg and trigger a scenery-path error during startup. If the BGL files were mixed into a shared folder, remove only the files documented as belonging to that package.