SE3kit

SE3kit is a lightweight Python library designed for 3D rigid-body transformations and rotations. It provides intuitive wrappers for homogeneous transformations, rotation representations (matrices, Euler angles, quaternions), and geometric primitives.

🚀 Features

• Rigid Body Transformations: Easy-to-use 4x4 homogenous transformation matrices (Transformation).
• Rotations: Comprehensive 3x3 rotation matrix support with conversions to/from Euler angles, Quaternions, and Axis-Angles (Rotation).
• Translations: Vector arithmetic and unit management (Translation).
• Homogeneous Points: 4D point representation for SE(3) operations (HPoint).
• ROS Integration: Seamless conversion between SE3kit objects and ROS geometry_msgs.

📦 Installation

This library is pure Python with minimal dependencies (numpy, numpy-quaternion).

From PyPI (Recommended)

To install the latest stable version from PyPI:

pip install se3kit

From Source

To install the library in editable mode from source:

git clone https://github.com/daniyalmaroufi/se3kit.git
cd se3kit
pip install -e .

For Development

For contributors, install the development dependencies (testing, linting, docs):

pip install -e '.[dev]'
pre-commit install

📚 Documentation

Full API documentation is available at: 👉 https://daniyalmaroufi.github.io/se3kit/

🛠 Usage

Rigid Body Transformations

Create and compose transformations intuitively:

import se3kit as se3

# Create a transformation: 1 meter up in Z, identity rotation
t1 = se3.Transformation(se3.Translation([0, 0, 1]), se3.Rotation())

# Compose transformations
t2 = se3.Transformation(
    se3.Translation([0.5, 0, 0]),
    se3.Rotation.from_rpy([0, 0, 1.57])  # Rotate 90° around Z
)

t_combined = t1 * t2

3D Point Transformation

Transform homogeneous points efficiently:

import se3kit as se3

p = se3.HPoint(0.1, 0.5, 0.0)
p_transformed = t_combined.transform_hpoint(p)

print(p_transformed.xyz)   # Access as standard 3D vector

Homogeneous Point (HPoint) Representation

Store and manipulate 3D points in either Cartesian or Full Homogeneous Form

import se3kit as se3
import numpy as np

# Cartesian coordinates
p1 = se3.HPoint(0.2, 0.4, 0.1)

# From NumPy array
p2 = se3.HPoint(np.array([1.0, 2.0, 3.0]))

# From full homogeneous vector
p3 = se3.HPoint(np.array([0.5, 0.0, 1.0, 1.0]))

print(p1.xyz)          # [0.2, 0.4, 0.1]
print(p2.as_array())   # Full 4×1 homogeneous vector

Transform a Homogeneous Point (HPoint)

Transform points attached to a robot’s tool through the end-effector pose.

import se3kit as se3

# A tool point on the robot’s end effector
tool_point = se3.HPoint(0.1, 0.0, 0.0)

# End-effector pose in world frame
T_world_ee = se3.Transformation(
    se3.Translation([0.5, 0.2, 1.0]),
    se3.Rotation.from_rpy([0, 0, 1.57])
)

p_world = T_world_ee.transform_hpoint(tool_point)
print(p_world.xyz)

Kinematic Chain Representation

Compose multiple transformations to represent an entire robot arm’s kinematic chain.

import se3kit as se3

# Example arm links
T1 = se3.Transformation(se3.Translation([0, 0, 0.4]), se3.Rotation.from_rpy([0, 0, 0.5]))
T2 = se3.Transformation(se3.Translation([0, 0, 0.3]), se3.Rotation.from_rpy([0, 0.2, 0]))
T3 = se3.Transformation(se3.Translation([0.1, 0, 0]), se3.Rotation.from_rpy([0.1, 0, 0]))

T_end_effector = T1 * T2 * T3

print(T_end_effector.as_geometry_pose())

Scaling and Unit Conversions

Seamlessly convert between millimeters and meters for transformations.

import se3kit as se3

T_mm = T_end_effector.convert_m_to_mm(inplace=False)
T_m  = T_mm.convert_mm_to_m(inplace=False)

print(T_mm.translation.xyz)

🤝 Contributing

We welcome contributions! Please follow these steps to ensure a smooth workflow:

1. Install Hooks: Run pre-commit install to set up linting hooks.
2. Test Locally: Run python -m unittest discover -v to ensure all tests pass.
3. Lint: Code is automatically formatted with black and ruff on commit.

📄 License

Distributed under the Apache 2.0 License. See LICENSE for more information.