WiTwin Core

WiTwin Core (witwin on PyPI, imported as witwin.core) describes a physical world in a form every WiTwin solver can read. A Scene holds structures (a geometry plus a material) and antenna endpoints. Optional trajectories and deformations make it move over time. Core does not simulate anything. Maxwell, Radar and Channel each take a Core scene and compile it into their own GPU resources.

Use Core directly when you:

• build a scene once and hand it to more than one solver;
• need differentiable geometry: signed distances, soft occupancy masks and triangle meshes that keep the PyTorch autograd graph;
• write a solver or a tool that must understand WiTwin scenes.

This documentation covers witwin 0.4.0. It is a pure-Python package that needs CPython 3.10 to 3.14, PyTorch 2.10 or newer and NumPy 1.24 or newer. See Installation.

Example#

Describe a room with one wall and two antennas, and ask the wall for its complex permittivity at 3.5 GHz:

from witwin.core import AntennaState, Box, PhysicalMaterial, Scene, Structure
 
concrete = PhysicalMaterial(eps_r=5.24, sigma_e=0.05, name="concrete")
wall = Structure(Box(position=(4.0, 0.0, 1.5), size=(0.2, 6.0, 3.0)), concrete, name="wall")
scene = Scene(
    structures=[wall],
    endpoints=[AntennaState(1, "tx", (0.0, 0.0, 1.5)), AntennaState(2, "rx", (2.0, 0.0, 1.5))],
)
 
print(concrete.evaluate_at_frequency(3.5e9).eps_r)  # (5.24-0.25678719406460493j)

What Core provides#

The supported public API is exactly the set of names in witwin.core.__all__. Import from witwin.core. Other modules can change between releases.

How Core fits in WiTwin#

Core sits under the solvers. witwin-channel 0.5.0 requires witwin==0.4.0; witwin-maxwell 0.5.1 and witwin-radar 0.4.1 require witwin>=0.4,<0.5. Each solver installs Core for you. Maxwell re-exports the Core geometry classes, and its Material extends PhysicalMaterial. Channel and Radar take a Core Scene or DynamicScene as input.

Where to go next#

Core is released under the MIT license.