⚠️ 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.

Translation

Move entities by modifying their translation over time.

Introduction

Translation moves an entity in world space. Modify transform.translation.x, .y, .z to change position. Scale movement by time.delta_secs() for frame-rate independence.

from pybevy.prelude import *
import math

Setup and Movement

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))),
    )
    commands.spawn(PointLight(shadows_enabled=True), Transform.from_xyz(4.0, 8.0, 4.0))
    commands.spawn(Camera3d(), Transform.from_xyz(0.0, 3.0, 8.0).looking_at(Vec3.ZERO, Vec3.Y))
 
 
def move_cube(time: Res[Time], query: Query[Mut[Transform], With[Mesh3d]]) -> None:
    for transform in query:
        transform.translation.x = math.sin(time.elapsed_secs()) * 3.0
        transform.translation.y = 0.5 + math.cos(time.elapsed_secs() * 2.0) * 1.0

Running the App

@entrypoint
def main(app: App) -> App:
    return (
        app
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .add_systems(Update, move_cube)
    )
 
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 translation.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.