Inertia - Physics Motion Response System - F4SE

This mod adds weight-based movement inertia and realistic cornering deceleration to Fallout 4, making heavy equipment feel more stable, acceleration smoother, reverse stronger, and combat more immersive.

Author's words:

introduction

In the original Fallout 4, player movement felt very responsive and game-like, but lacked a sense of physical weight and momentum. Characters can accelerate, stop, and reverse in an instant without ever feeling grounded.

This creates a subtle break in immersion. Carrying heavy gear should affect how you move, how quickly you change direction, and how stable you are during tight turns.

This module directly introduces weight-based motion inertia at the engine level. Acceleration and deceleration are adjusted smoothly, and the load-to-weight ratio dynamically affects the response.

Heavier gear will result in slower acceleration, more drag in reverse, and more noticeable momentum. Sharp turns can cause real deceleration, especially when carrying a heavy load.

Inspired by modern tactical shooters known for grounded controls and weight simulations, the system brings a more realistic sense of movement to Federation without sacrificing responsiveness.

The goal is not to make movement clunky or artificially difficult, but to restore logical physical behavior and believable player momentum while keeping controls smooth and responsive.

Configuration

The mod is fully configurable via the INI file included in the F4SE plugin folder.

All game parameters such as acceleration, deceleration, weight effects, reversing behavior and cornering deceleration can be adjusted to match your preferred movement style.

Each setting in the INI file is clearly described, allowing you to fine-tune the balance between responsiveness and realism. Whether you prefer delicate momentum or a heavier, more tactical feel, the system can be customized to fit your play style.

Custom INI override

The mod supports a flexible INI override system, allowing additional configuration files to modify the main settings without modifying the base Inertia.ini.

Overlay files can be placed in the Data\F4SE\Plugins\InertiaCustomINI folder. The mod will automatically load every .ini file found in this directory and apply their settings on the main configuration.

Files are processed in alphabetical order, meaning that subsequent files can overwrite values ​​from previous files. This allows mod lists or patches to adjust specific parameters without leaving the original configuration unchanged.

When launched, the mod writes details to a log file, including which override files were detected and which settings were overridden. This makes it easy to verify that custom configurations are applied correctly.

Multiple overlay files can be used simultaneously, making it easy to separate different tweaks, patches or balance changes into separate configuration files.

Compatibility and additional information

Debugging only works with WASD keys.

Install

Install the mod using your favorite mod manager.

Available game versions: OG (1.10.163) and the latest version of AE, uninstall at any time.

The compressed package contains files that support version V1.6.3.