⚠️ Beta State

PyBevy is in an early and experimental stage. The API is incomplete, subject to breaking changes without notice, and you should expect bugs. Many features are still under development.

3D Rotation

Rotate a 3D object around different axes.

Introduction

3D rotation uses quaternions internally, but PyBevy provides helper methods like rotate_x(), rotate_y(), and rotate_z() for convenience.

from pybevy.prelude import *
from math import pi

Setup

def setup(
    commands: Commands,
    meshes: ResMut[Assets[Mesh]],
    materials: ResMut[Assets[StandardMaterial]],
) -> None:
    commands.spawn(
        Mesh3d(meshes.add(Cuboid.from_length(1.0))),
        MeshMaterial3d(materials.add(Color.srgb(0.3, 0.5, 0.9))),
        Transform.from_xyz(0.0, 0.5, 0.0),
    )
    commands.spawn(PointLight(shadows_enabled=True), Transform.from_xyz(4.0, 8.0, 4.0))
    commands.spawn(Camera3d(), Transform.from_xyz(-3.0, 3.0, 5.0).looking_at(Vec3.ZERO, Vec3.Y))

Rotation System

def rotate(time: Res[Time], query: Query[Mut[Transform], With[Mesh3d]]) -> None:
    for transform in query:
        transform.rotate_y(time.delta_secs())
        transform.rotate_x(0.5 * time.delta_secs())

Running the App

@entrypoint
def main(app: App) -> App:
    return (
        app
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .add_systems(Update, rotate)
    )
 
if __name__ == "__main__":
    main().run()

Running this example

Use PyBevy's hot reload feature to run and develop this example. If you don't have PyBevy installed, check out the Quick Start guide.

$pybevy watch 3d_rotation.py

The code will reload automatically when you make changes to the file.

From Python to Rust

Notice how the core concepts in the code—Commands, Assets, App, and Systems—are identical to the original Bevy example?

This is the power of pybevy! It lets you learn Bevy's powerful, data-driven architecture in friendly Python.

When your project grows and you're ready for maximum, native performance, you'll already know the concepts to start writing systems in Bevy Engine with Rust.