Modders add collision to low poly 3D models by creating simple, geometry-matching shapes (e.g., boxes, spheres, convex hulls) in 3D software or game engine tools.
This balances accuracy and performance—low poly models don’t need high-detail collisions, so basic shapes align with the model’s outline while keeping mods lightweight for games.
For Blender, use the Collision modifier; in Unity/Unreal, add built-in components like Box Collider. Test in-game to ensure natural interactions (e.g., a low poly crate moving realistically).