Understanding the Prepar3D Scenery Library Architecture

The Prepar3D (P3D) scenery library is the backbone of your simulation’s visual environment. It controls how every piece of terrain, airport, landmark, and custom object is loaded and displayed. At its core, the library relies on a configuration file named scenery.cfg, which lists all installed scenery areas in a specific priority order. When P3D starts, it reads this file and loads scenery layers from top to bottom. Higher layers (those listed first) take precedence over lower ones when multiple add-ons cover the same geographic area or airport.

Misconfigured scenery layers are a common source of issues for AeroSimulations users. Incompatible or duplicate entries can cause missing buildings, flickering textures, or even crashes. Because AeroSimulations add-ons often modify airport layouts, taxiways, and apron textures, proper scenery library configuration is essential to ensure these customizations appear correctly without conflicting with default or other third-party scenery.

Each entry in the scenery.cfg file points to a folder containing BGL files (scenery binaries), texture files, and sometimes additional configuration. The priority order determines which BGL files are loaded first. When two scenery areas cover the same airport, the one with higher priority (listed earlier) will dominate. Understanding this hierarchy is the first step to achieving seamless AeroSimulations compatibility.

Pre-Configuration Preparations

1. Backup Your Current Scenery Library

Before making any changes, you must create a backup of your existing scenery configuration. Locate the scenery.cfg file in your %APPDATA%\Lockheed Martin\Prepar3D v5 folder (or version-specific path). Copy this file to a safe location. Additionally, note the folder structure of your custom scenery – you may want to back up the entire Add-on Scenery directory if you have custom layouts. A backup ensures you can revert to a working state if something goes wrong during optimization.

2. Organize Your Scenery Folder Structure

A clear, consistent folder structure simplifies management and reduces errors. Create dedicated folders for different scenery categories:

  • Default Scenery – Leave untouched as installed by P3D.
  • Add-on Scenery – A main folder where all third-party scenery resides (e.g., Add-on Scenery\AeroSimulations\KLAX).
  • Custom Scenery – For user-created or modified files that should override default and add-on content.

Use descriptive subfolder names that include the airport ICAO code or region. Avoid using spaces or special characters in folder names to prevent path parsing issues. If you have many add-ons, consider using a folder naming convention like ZZZ_AeroSimulations_KLAX – the "ZZZ" prefix helps when sorting alphabetically in third-party tools.

For advanced users, symbolic links can help keep your scenery organized without moving large files. For example, you can link a network drive or an SSD-optimized folder into your P3D scenery path. However, ensure that symbolic links are created with administrative privileges and that the linked folder contains the correct subfolder structure (e.g., scenery and texture). This method can improve performance if you load scenery from fast storage while keeping your main installation clean.

Manual Editing of the scenery.cfg File

Directly editing the scenery.cfg file gives you fine-grained control over layer priority. Use a text editor like Notepad++ with administrator rights to modify the file. The file contains sections like [General] and multiple [Area.XXX] entries. Each area entry has a Local= path and an optional Layer= parameter. The order of the [Area.XXX] sections in the file determines loading priority – the first section listed is treated as the top layer.

For optimal AeroSimulations compatibility, follow this general priority hierarchy from top to bottom:

  1. High-priority custom airports – Add-ons like AeroSimulations that replace entire airport layouts. These must be above any default airport or other modifications.
  2. Regional scenery enhancements – Mesh, landclass, and vector data that cover wide areas.
  3. Default P3D scenery – The base scenery that comes with the simulator.
  4. Global base textures and mesh – Base corrections that should only fill gaps.

Important: If you have multiple AeroSimulations products for airports that are geographically close, you may need to fine-tune the order. Usually, the more detailed airport (higher poly count, more custom objects) should be placed higher. If two add-ons modify the same airport, the higher-layer one will completely overwrite the other – so ensure you only have one active scenery for each airport.

Editing the Layer Parameter

Each area entry may include a Layer= value. This value is used by P3D's scenery manager to reorder entries when you use the in-sim interface, but manual editing bypasses that. You can safely ignore the Layer= number; what matters is the physical order of the [Area.XXX] blocks. To move an entry up, cut and paste the entire [Area.XXX] block to an earlier position in the file. After editing, save the file and restart P3D for changes to take effect.

Using Third-Party Scenery Managers

While manual editing is powerful, third-party tools simplify the process and provide visual feedback. The most popular options include:

  • Scenery Library Manager (SLM) – A lightweight tool that lets you drag-and-drop entries, enable/disable layers, and save profiles. SLM reads and writes the scenery.cfg file directly. This tool is especially useful for quickly testing different orders for AeroSimulations add-ons. An alternative is Lorby Scenery Editor, which offers additional features like batch editing and conflict detection.
  • P3D Scenery Config Editor (SCE) – This tool can manage multiple scenery.cfg versions and even handle add-on.xml entries for newer P3D versions (v4+). It can also flag duplicate airports or missing paths.
  • Airport Design Editor (ADE) – While primarily for airport design, ADE can open scenery.cfg and display a list of all airports covered by each scenery entry. This helps identify conflicts quickly.

Tip: After using any third-party manager, always double-check the resulting scenery.cfg file in a text editor. Some tools may change the file format or add extra blank lines. A clean file with consistent spacing reduces the risk of parse errors.

Optimizing Scenery Library Specifically for AeroSimulations

AeroSimulations products are known for their detailed, high-resolution airport presentations. To ensure these add-ons display correctly, you must prioritize their scenery layers and manage conflicts with default and other add-on airports.

Setting Correct Priority for AeroSimulations Airports

Place your AeroSimulations scenery entries at the very top of the scenery.cfg file, above all other scenery including default airports. For example, if you have AeroSimulations KLAX and default KLAX, the AeroSimulations version should be listed first. If you have multiple AeroSimulations airports, order them by largest or most complex first, but generally any order among them is fine as long as they don’t overlap geographically.

Disabling Duplicate Default Airports

P3D includes default airports that will conflict with AeroSimulations versions. To disable a default airport, you can either:

  • Locate the default airport’s BGL file (usually in Scenery\0000\APX or Scenery\0502 for smaller regions) and rename it with a .off extension. Note that this disables the airport globally, not just for AeroSimulations. To only disable default for a specific area, you can create an exclusion BGL file using ADE.
  • Use the “Exclude” functionality in the scenery.cfg by adding a layer with an exclude area – but this is advanced and error-prone.

Most AeroSimulations products come with an installer that attempts to disable default airports automatically. Verify by checking the Scenery Library Manager – if the default airport still appears as active, disable it manually.

Resolving BGL File Conflicts

Sometimes two scenery add-ons may both modify the same airport but for different aspects (e.g., one modifies taxiways, another adds 3D objects). In such cases, you can use a technique called “Layer Override” by placing the more detailed scenery higher, but if both are essential, you may need to merge BGL files using tools like BGLComp. This is beyond basic configuration; for most users, simply ensuring only one active scenery per ICAO is sufficient.

Advanced Configuration Techniques

Using Area.xxx Entries Correctly

P3D uses numbered area entries (e.g., [Area.001]). If you manually add entries, ensure the numbering is sequential and does not skip numbers. Some third-party tools automatically renumber; if you edit manually, you may need to renumber the entire file. A missing or duplicate area number can cause P3D to ignore that scenery.

Handling Add-on.xml and Add-on.cfg

Since P3D v4, some add-ons use an add-on.xml file to register themselves. These are managed in the add-ons.cfg file located in the same %APPDATA% folder. For AeroSimulations products that support this method, you do not need to add them to scenery.cfg – they are loaded via the Add-ons menu in P3D. However, you may still need to adjust the loading order via the in-sim Add-ons dialog. Ensure that any add-on.xml scenery appears in the correct order relative to traditional scenery.cfg entries.

Memory and Performance Optimization

Too many active scenery layers can degrade performance. If you have many AeroSimulations products for airports you rarely fly to, consider disabling them by removing their entries or creating a separate scenery.cfg profile. Use a scenery manager to create profiles for different regions or aircraft types. This reduces the load on your CPU and GPU during flight and speeds up initial loading times. Additionally, set texture resolution in the P3D options to match your hardware – high-resolution textures from AeroSimulations can consume significant VRAM.

Troubleshooting Common Issues

Missing Airport Buildings or Black Textures

If an AeroSimulations airport shows missing objects or black textures, it often indicates a layer priority conflict. Check that the AeroSimulations entry is above any default airports covering the same region. Also verify that the AeroSimulations texture folder is complete and that no third-party texture replacement mods (like Orbx Global) are overwriting the files. Try temporarily disabling all other add-ons to isolate the conflict.

Crashes to Desktop (CTD) After Installing AeroSimulations

CTDs can occur if the scenery.cfg has a missing path (the folder no longer exists) or if a BGL file is corrupted. Run a scenery library validation using a tool like Lorby Scenery Editor – it can scan for invalid entries. Common causes: moving a scenery folder without updating the path, or exceeding the maximum number of area entries (P3D v5 allows up to 600 entries). If you have many add-ons, consider merging some using composite BGL files.

Water Reflections or Landclass Issues Around Airports

Sometimes an AeroSimulations airport may appear to float over water or have wrong landclass. This usually means a mesh or landclass add-on (e.g., FS Global Ultimate) is overriding the airport’s flatten effect. Ensure that any terrain mesh add-ons are placed below the AeroSimulations airport entry in the scenery library (i.e., lower priority). The airport’s flatten BGL must be loaded after the mesh to take effect. If the problem persists, use ADE to adjust the airport altitude and exclude mesh in the immediate area.

Maintaining Your Scenery Library Over Time

A well-configured scenery library is not a one-time setup. As you add new AeroSimulations products or other add-ons, conflicts can re-emerge. Follow these maintenance practices:

  • After each new installation, open your scenery manager and verify the layer order. New add-ons often install at the bottom of the list, which may cause them to be overridden.
  • Keep a log of which airports you have AeroSimulations for, and periodically check for duplicate ICAO codes in your library.
  • Use the “Test Flight” mode in P3D to quickly jump to a specific airport and verify that custom objects load correctly. If you see default objects or missing elements, adjust layer priority.
  • Backup your optimized scenery.cfg file after each major change – label it with the date and list of active add-ons.

Additionally, monitor P3D updates. Major version updates (e.g., v5 to v5.2) sometimes change how scenery.cfg is read or introduce new parameters. Check the official P3D support page for any scenery-related changes. AeroSimulations may also release patches for compatibility with newer P3D builds – keep your add-ons up to date.

Final Recommendations

Configuring your Prepar3D scenery library for better AeroSimulations compatibility requires careful attention to layer priority, conflict resolution, and file organization. Start by backing up your current setup, then manually reorder your scenery.cfg or use a reliable third-party manager. Place AeroSimulations airports at the top, disable duplicate default airports, and ensure all paths are correct. Regularly test and maintain your configuration to avoid performance degradation over time.

By investing a few hours to optimize your scenery library, you will enjoy smoother flights, accurate airport details, and a more immersive simulation environment. The effort pays off every time you see an AeroSimulations airport exactly as the developer intended, without visual glitches or loading delays. For further reading, refer to the official P3D SDK documentation on scenery installation and the AeroSimulations support portal for product-specific tips.