rillfacet

A fast 3D viewer for simulations. Feed it plain arrays; get an interactive scene in a native window or in your browser.

• Simple. Meshes, points, curves, volumes and arrows, colored by any quantity you attach.
• Fast. WebGPU rendering with soft shadows, ambient occlusion and transparency.
• Everywhere. Python, C++, and a browser client that streams from a running process.
• Independent. It never depends on a simulator. NumPy and torch tensors (CUDA too) just work.

The name: a rill is a small stream, like the stream of poses and meshes flowing from your simulator. A facet is one flat face of a mesh, or the flat near and far planes that bound what a camera sees.

Python

pip install rillfacet

Start with examples/hello.py: a rippling sheet colored by height, in about 50 lines with no simulator.

Plugging in your own simulator looks like this:

import rillfacet as viz

v = viz.Viewer()
cloth = v.scene.add_mesh("cloth")
cloth.set_geometry(verts, tris)
cloth.add_scalar("speed", viz.ElementKind.Vertex, speed)
cloth.color_source = viz.ColorSource.Quantity
cloth.color_quantity = "speed"
cloth.colormap = "viridis"

def callback():              # runs every frame
    sim.step()
    cloth.set_positions(sim.positions)

v.set_callback(callback)
v.run()

Use Viewer(headless=True) to render offscreen, for screenshots and CI. Your own panels use the familiar imgui API.

Look closer

Switch styles and themes, see through to the wireframe, or slice a volume open to inspect what is inside.

Select vertices, edges, faces or bodies. Measure distances and angles. Drag objects with the mouse. Controls follow Blender.

C++

Link the static library and use the same scene API. The bundled demo needs no simulator:

./build/showcase

In the browser

Stream a live run, or replay saved ones, in any WebGPU browser. The browser renders the same shaders as the native window.

from rillfacet.scene_api import Scene
from rillfacet.web.server import StreamBackend, VizServer

server = VizServer("0.0.0.0", 8080)
backend = StreamBackend(server.stream("live"))
scene = Scene(backend)

if backend.wanted():             # a browser is watching
    backend.commit(scene, time=step)

Open http://<host>:8080/. It suits physical simulation and reinforcement learning alike; the clip below shows robots from a training run.

Requirements

• Linux x86-64 and Python 3.10 or newer.
• A Vulkan driver (your GPU's, or Mesa's software one).
• Optional: ffmpeg to record .mp4 video.

Build from source

./scripts/build_dawn.sh                      # once, about 10 minutes
cmake -S . -B build -G Ninja && cmake --build build
pip install .                                # the Python wheel

You need GCC 13 or newer (or Clang), CMake 3.24 or newer, Ninja and git. Full details, the complete API notes and the controls table are in docs/REFERENCE.md.

License

MIT. Wheels also bundle Dawn, GLFW, Dear ImGui, ImPlot, nanobind and fonts under their own licenses; see THIRD_PARTY_LICENSES.txt.