How Developers Make Destructible Environments in Games

Creating fully destructible environments in video games requires a complex blend of physics engines, procedural generation, and clever optimization techniques. This article explores the primary methods game developers use to achieve realistic and satisfying environmental destruction—including voxel technology, pre-fractured meshes, and real-time physics simulations—while maintaining stable game performance.

Pre-Fractured Meshes and Rigid Body Physics

The most common method for creating destructible objects is the pre-fractured mesh technique. Instead of calculating how an object breaks in real-time, developers design the object’s broken pieces beforehand.

Using 3D modeling software or game engine tools, developers apply algorithms (such as Voronoi diagrams) to slice a 3D model into smaller chunks. In the game, the object exists as a single, undamaged mesh. The moment an impact occurs, the engine instantly swaps the undamaged model with the pre-fractured pieces and applies rigid body physics to them, causing the chunks to fly apart, roll, and settle realistically.

Voxel-Based Destruction

Voxels (volumetric pixels) are the 3D equivalent of 2D pixels. Unlike traditional 3D models which are hollow shells, voxel worlds are made of individual, solid blocks of data.

Because every voxel carries information about its position, color, and material type, developers can easily manipulate them in real-time. When an explosion occurs in a voxel-based game, the engine simply deletes the voxels within the blast radius and subjects the surrounding voxels to gravity. This allows for highly detailed, microscopic destruction where players can carve precise holes through walls and terrain.

Procedural Real-Time Slicing

For games that require dynamic cutting—such as sword-fighting games where objects can be sliced at any angle—developers use procedural real-time fracturing.

When a cutting force intersects a mesh, the game engine calculates the exact plane of the cut. It then dynamically generates new geometry and UV coordinates to seal the exposed insides of the two newly created pieces. Because this process requires significant mathematical calculation on the fly, it is usually reserved for specific gameplay mechanics rather than entire destructible cities.

Structural Integrity and Connectivity Graphs

To prevent buildings from floating unrealistically when their foundations are destroyed, developers implement structural integrity systems.

This is achieved using a “connectivity graph” or support network. The game engine continuously checks if a structural piece is connected to the ground, either directly or through adjacent pieces. If a chunk of a wall loses its connection to any grounded support beams, the physics engine activates gravity for that chunk, causing the unsupported section of the building to collapse.

Optimization Techniques

Simulating thousands of individual debris pieces can quickly overwhelm a computer’s CPU and GPU. To maintain playable frame rates, developers use several optimization tricks:

• Debris Culling: Small rocks, dust, and minor debris are programmed to fade away or disappear after a few seconds.
• Sleep States: Once a fractured piece stops moving, the physics engine puts it to “sleep,” stopping all physics calculations for that object until it is disturbed again.
• Particle FX Swapping: Large explosions are often masked with heavy smoke and dust particle effects. This hides the moment the game engine swaps the unbroken mesh for the broken debris.