Assetto Corsa Competizione: Best graphics.json for VR Clarity

Achieving visual clarity in ACC VR is a balancing act between Super Sampling and Temporal Anti-Aliasing (TAA). The game’s deferred rendering pipeline often causes a “shimmering” effect on fences and distant track markers, which can be nauseating in a VR headset. By manually editing the graphics.json, we can force the engine to use a more aggressive sharpening mask and optimize the VR pixel density beyond what the in-game sliders allow.

File Path

To access the core graphics configuration of ACC, navigate to the following directory on your PC:

Documents\Assetto Corsa Competizione\Config\graphics.json

Note: Ensure the game is completely closed before editing. It is highly recommended to disable the “Steam Cloud” sync for ACC temporarily while making these changes to prevent the launcher from overwriting your custom JSON values.

graphics.json Configuration Block

Locate the section within the JSON file and update the following parameters. These values are specifically tuned for high-fidelity VR headsets (e.g., Quest 3, Valve Index, HP Reverb G2):

{
	"vrPixelDensity": 1.4,
	"resolutionScale": 100,
	"antialiasingQuality": 4,
	"antialiasingType": 2,
	"postProcessQuality": 0,
	"mirrorQualityLevel": 1,
	"temporalAASelection": 1,
	"shadingRate": 0,
	"sharpeningAmount": 1.5,
	"sharpeningThreshold": 0.5,
	"foveatedRendering": 1,
	"foveatedRenderingIntensity": 2,
	"useCAS": 1
}

Technical Breakdown and Performance Analysis

The following parameters are the pillars of VR clarity in the Unreal Engine 4 racing pipeline:

Parameter	Recommended Value	Technical Impact
vrPixelDensity	1.4 – 1.6	Sets the internal VR render resolution. Increasing this is the single best way to eliminate blur.
antialiasingType	2 (Temporal AA)	Required for the engine to function correctly, but needs high sharpening to look clear.
sharpeningAmount	1.5	Applies a strong Contrast Adaptive Sharpening (CAS) pass to counteract TAA blur.
foveatedRendering	1	Renders the edges of your vision at a lower resolution, freeing up GPU power for the center “Sweet Spot.”
postProcessQuality	0	Disables Bloom and Depth of Field, which are unnecessary and clarity-reducing in VR.

HowTo: Implementing the VR Clarity Fix

To ensure these settings result in a crisp image without crashing your frametime (ms), follow these steps:

1. Backup: Create a copy of graphics.json and name it graphics_backup.json.
2. Adjust Pixel Density: If your FPS is below 90, lower vrPixelDensity to 1.2. If you have an RTX 4090, you can push this to 1.8 for extreme clarity.
3. Enable CAS: Ensure useCAS is set to 1. AMD’s Contrast Adaptive Sharpening works on both NVIDIA and AMD GPUs and is superior to the default UE4 sharpening.
4. Save & Read-Only: Save the JSON file. Right-click it, select Properties, and check Read-only to prevent ACC from resetting your vrPixelDensity to 1.0.
5. In-Game Setting: Once in the cockpit, go to Video Settings and ensure “Motion Blur” is set to OFF. In VR, motion blur causes instant loss of depth perception.

Technical Explanation: Overcoming TAA Ghosting in VR

The “ghosting” or “smearing” effect on the asphalt in ACC VR is caused by the Temporal Anti-Aliasing algorithm’s inability to reconcile high-speed movement across the stereo buffers of a VR headset. By setting antialiasingQuality to 4 and increasing vrPixelDensity, we provide the TAA algorithm with more “raw data” (pixels) to work with. This reduces the margin of error for the temporal reprojection, resulting in a much more stable image. Combined with a high sharpeningAmount, the result is a clean, sharp look that allows you to read your dashboard and braking markers even at 250 km/h.