Physics Engine Fundamentals

Understand Garry's Mod physics: gravity, mass, friction, momentum, and collision. Learn how the engine impacts your creations.

2.1. Physics Engine Fundamentals

Garry's Mod is built upon a powerful physics engine, primarily the Havok physics engine, which dictates how objects interact in the game world. Understanding these fundamentals is key to creating stable structures, functional vehicles, and predictable contraptions. This section explores the core concepts of physics simulation within GMod.

The physics engine in Garry's Mod simulates real-world physics, including gravity, mass, friction, and momentum. Every prop you spawn has inherent physical properties that influence its behavior. Gravity constantly pulls objects downwards, while mass determines how resistant an object is to changes in its motion. Friction affects how objects slide against each other, and momentum is the measure of an object's motion, dependent on its mass and velocity.

Key Physics Concepts:

• Gravity: The force pulling all objects towards the center of the planet (or the map's origin). You can adjust gravity using the 'Gravity Gun' or console commands.
• Mass: A measure of an object's inertia. Heavier objects are harder to move and have more impact when they collide.
• Friction: The resistance to motion when two surfaces are in contact. High friction means less sliding.
• Momentum: The product of an object's mass and velocity. An object with high momentum is difficult to stop.
• Collision: When two physical objects occupy the same space, they exert forces on each other. The outcome of a collision depends on their mass, velocity, and material properties.

The Tool Gun plays a crucial role in manipulating these physics properties. Tools like the Weld, Constraint, and Physics Gun allow you to override or enhance the default physics behavior. For instance, welding two objects makes them behave as a single, larger object with combined mass and inertia. Using constraints can create joints that allow for controlled movement, mimicking real-world hinges or pistons.

Understanding how these elements interact is vital for building. A poorly constructed vehicle might fall apart because its welded components can't withstand the forces applied during movement. Similarly, a bridge might collapse if its supports are not strong enough to bear the weight of the props placed upon it. Experimenting with different props and observing how they react to forces is the best way to build an intuitive understanding of GMod's physics.