Microsoft Flight Sim: Best UserCfg.opt for VR Cloud Fix

The “Cloud Fix” involves disabling FilmGrain and Sharpening within the VR-specific section of the config file. Many users make the mistake of only editing the “Graphics” section, which does not apply to the VR runtime.

File Path

The location depends on your platform. Ensure the game is closed before editing.

• Microsoft Store: %LOCALAPPDATA%\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalCache\UserCfg.opt
• Steam: %APPDATA%\Microsoft Flight Simulator\UserCfg.opt

Technical Note: To verify the fix, look for the {GraphicsVR header. Any changes made under {Graphics (the desktop section) will not affect your VR experience.

Optimized “Clean Skies” Configuration Block

Open the file with Notepad and search for the {GraphicsVR block. Scroll down to the {PostProcess section within that block and apply these values:

Parameter	Recommended Value	Technical Purpose
Sharpen	0	Mandatory. Removes the “halo” effect on cloud edges caused by post-process sharpening.
FilmGrain	0	The Grain Fix. Disables the overlay noise that makes clouds look “pixelated.”
Dirt	0	Removes lens smudges that can look like “dots” on the clouds.
Fringe	0	Disables Chromatic Aberration, preventing color-bleeding in peripheral vision.
EyeAdaptation	0	Optional. Prevents the “blinding” effect when flying through clouds.

{GraphicsVR
    ...
    {PostProcess
        Enabled 1
        EyeAdaptation 0
        ColorGrading 1
        Sharpen 0
        Fringe 0
        LensDistortion 0
        Dirt 0
        LensFlare 0
        FilmGrain 0
        Vignette 0
        LensBlurMultiplier 1.000000
        FringeMultiplier 1.000000
    }
}

HowTo: Engineering the Ultimate VR Cloud Clarity

Follow these GameEngineer.net technical steps to ensure the fix sticks and the visuals remain stable:

1. Read-Only Warning: If you change any graphics settings in the game menu, the sim will overwrite your manual UserCfg.opt edits. After saving the file, right-click it, go to Properties, and check Read-only.
2. Volumetric Clouds (Medium vs. Ultra): In VR, setting clouds to Ultra is often less about detail and more about reducing “flicker.” Ultra uses a higher sample rate for ray-marching. If your GPU allows, use Ultra for clouds while lowering Terrain LOD to compensate for the FPS hit.
3. Foveated Rendering (Foveation): If using the 2024 build or OpenXR Toolkit, ensure “Eye Tracked Foveated Rendering” is stable. In Sim Update 4, this caused clouds to “wobble” or jump independently of the cockpit. If clouds feel “unstable,” switch to Fixed Foveated Rendering.
4. DLSS + Sharpening (NVIDIA Only): If you use DLSS, the in-sim “Sharpening” slider should be set to 0%. Any sharpening applied to a volumetric cloud creates a grid of black/white pixels known as “dithering noise.”
5. Ignore Film Grain (NVIDIA Freestyle): If you use Nvidia filters (Alt+F3), ensure the “Ignore Film Grain” slider is set to 100%. This prevents the driver from trying to “enhance” the very grain you just disabled in the config.

Technical Explanation: Ray-Marching and Post-Process Conflict

The pixelated cloud look is a result of Temporal Anti-Aliasing (TAA) struggling with Volumetric Ray-Marching. The clouds are rendered as a series of 3D boxes ($Voxels$). To save performance, the engine doesn’t render every pixel every frame; it uses a dithered pattern and fills the gaps using data from previous frames ($T_{n-1}$).

When the Sharpen filter in the UserCfg.opt is active, it detects these dithered “gaps” as edges and highlights them. This creates the “grainy” or “screen door” effect on the clouds. By disabling FilmGrain and Sharpen, you allow the VR headset’s high-density optics to handle the image naturally, relying on the Supersampling of your VR runtime (OpenXR) rather than the game’s crude post-processing filters.