Assetto Corsa: Best ext_config.ini for Custom Shaders Patch

The goal for a master-tier CSP configuration is Atmospheric Realism without Clarity Loss. Many “Ultra” presets introduce too much glare or “God Rays” that obscure the apex of a corner. This configuration focuses on the [SMART_MIRROR], [LIGHTING_FX], and [WINDSCREEN_FX] modules to ensure that night racing and rain conditions look cinematic while maintaining a solid 144Hz+ for competitive driving.

Hardware Compatibility & Expectations

• VRAM and CSP: CSP’s “Extra Effects” (SSAO, SSLR) are heavy on VRAM. If you have 8GB or less, disabling “Local Reflections” (SSLR) in the general CSP settings is the best way to regain 20 FPS.
• CPU and Physics: CSP includes “Physics Extensions.” If your CPU is older, ensure “Extended Physics” is disabled in the drive menu to avoid “CPU Occupancy” warnings on large grids.
• The “Pure” Integration: This config assumes you are using Pure (the successor to Sol). Ensure your ext_config.ini doesn’t conflict with Pure’s dynamic weather scripts.

File Location

There are two types of ext_config.ini:

1. Global/General: Handled via Content Manager (Settings > Custom Shaders Patch).
2. Specific (Car/Track): [Assetto Corsa Folder]\extension\config\cars\mods\[car_name].ini or within the car’s own extension folder.

Best ext_config.ini for High-End Realism

If you are creating a custom config for a modded car or track, these are the essential blocks to include for a “Cinematic” feel:

1. [SMART_MIRROR] – Professional Visibility

Standard mirrors in AC are flat. Smart Mirrors allow for a 3D perspective that shifts with your head movement (essential for VR/TrackIR).

[SMART_MIRROR]
ENABLED = 1
REAL_MIRROR_PROJECTION = 1   ; Creates a true 3D reflection
VR_EYE_ITERATIONS = 2        ; Higher quality for VR users
WIDTH = 0.25                 ; Adjusts physical mirror size in the cockpit

2. [LIGHTING_FX] – Night Racing Depth

This controls how your headlights interact with the environment and the dashboard.

[LIGHTING_FX]
DYNAMIC_LIGHTS = 1
HEADLIGHTS_SATURATION = 0.8  ; Reduces "blinding" white light on signs
BOUNCE_LIGHTS = 1            ; Light reflects off the road back onto the car
INTERIOR_LIGHT_STRENGTH = 0.5

3. [WINDSCREEN_FX] – Cinematic Weather

If you have the paid version of CSP (Preview), this handles the rain physics on the glass.

[WINDSCREEN_FX]
REFRACTION = 1
USE_DYNAMIC_MASK = 1         ; Wipers actually clear the water realistically
BLUR_STRENGTH = 0.5          ; Simulates speed-based rain streaking

Strategy for Visual Clarity

• The “Neck FX” Sweet Spot: In the CSP settings, set Neck FX to lean into the turn slightly (15-20%). This mimics a real driver’s head movement and makes hitting the apex on tight tracks like Monaco or Mount Panorama much more intuitive.
• Brake Glow: Add [BRAKEDISC_FX] to your config to enable glowing discs. This isn’t just for show; in night endurance races, it helps you visually confirm if the car ahead is over-braking or “riding” the brakes.
• Tyre FX: Ensure [TYRES_FX] is active. It adds visual “flat spots” and dirt pickup on the tread, providing visual feedback on your driving style and tyre wear.

Key Performance Parameters (CSP General)

Feature	Recommended	Impact
Extra Effects (SSLR)	Low / Off	The #1 FPS killer. Turn off for a 25% performance gain.
Grass FX	Enabled	Vital for track realism, but set “Cast Shadows” to Off.
Particle FX	Active	Set “Smoke” to a low limit to avoid FPS drops in drift trains.
Weather FX	Pure	The most optimized way to handle 24-hour cycles.

Troubleshooting & Common Fixes

• Black Skies at Night: This is a conflict between CSP versions and Sol/Pure. Re-run the “Install Manual” steps for Pure and ensure “Weather FX” is pointed to the correct script.
• Headlights “Bleeding” through Cockpit: In your car’s ext_config.ini, use the [DEALS] or [MASK] block to prevent exterior lights from illuminating the interior floorboards.
• White Trees / Shiny Grass: This is a “Seasonal Adjustments” bug. In CSP settings, go to Weather FX and disable “Seasonal Track Textures” if the track looks like it’s covered in snow in July.

Frequently Asked Questions (FAQ)

Conclusion and Expected Results

By tailoring your ext_config.ini to prioritize “Smart” features over “Heavy” post-processing, you are modernizing Assetto Corsa without sacrificing the frame rates needed for sim racing. You can expect a perfectly aligned 3D mirror system, realistic night-time illumination that doesn’t wash out your dashboard, and the atmospheric immersion required for long-distance GT3 or Touge runs.