WebUI

The livn WebUI is a browser-based 3D visualization and Python console for interacting with neural systems. It renders neuron populations, electrode arrays, and bounding boxes in a Threlte/Three.js scene, driven entirely through a Python REPL powered by Pyodide.

Starting the UI

The WebUI requires two servers:

1. Backend server — serves system data files (and optionally HSDS)
2. Frontend dev server — serves the SvelteKit application

# Start the backend file server (port 5102)
livn ui server --launch

# In another terminal, start the frontend
livn ui web --launch

Open http://localhost:5173 in your browser.

Using the Console

The right panel is a Python REPL. Type standard livn Python code to load and inspect systems:

from livn.env import Env
from livn.system import predefined

env = Env(predefined('EI1'))

After each execution, the 3D scene updates automatically to reflect the current env state.

Loading electrodes

from livn.io import MEA
env.io = MEA.from_directory(env.system.uri)

Electrode positions appear as yellow wireframe cubes in the scene.

3D Scene

The left panel shows a 3D scene with:

• Neuron populations — colored spheres (blue for excitatory, red for inhibitory)
• Electrode array — yellow wireframe cubes at electrode positions
• Bounding box — wireframe outline of the system extent

Click on a neuron to see its GID, population, coordinates, and distance to the nearest electrode.

Use your mouse to orbit, zoom, and pan the camera.

View Controls

An overlay in the top-left of the scene provides visualization controls:

Control	Description
Population toggles	Show/hide individual populations
Point size	Adjust neuron sphere size (0.2×–3.0×)
Opacity	Adjust neuron transparency (10%–100%)
Bounding box	Toggle system bounding box wireframe
Electrodes	Toggle electrode markers

These controls affect only the visualization — they do not modify the Python env object.

Status Bar

The bottom bar shows:

• Backend type — "HSDS" or "pyfive (local)"
• Env state — which attributes are currently set (system, io, model)
• Execution time — duration of the last console command