Visualization

Numbers in a loop are great for tests; for everything else you want to see the simulation. DART 7 ships an interactive viewer and a curated set of demo scenes, and it can render frames headlessly for screenshots and CI.

Run the interactive demos

From a source checkout, the demo runner opens scenes in the viewer:

pixi run py-demos                                   # open the default scene
pixi run py-demos -- --scene rigid_body             # pick a scene by id
pixi run py-demos -- --list                         # list every scene

Each scene builds a real World, steps it live, and draws the result, with on-screen panels for tweaking parameters. Browsing the scene sources is one of the fastest ways to learn idiomatic DART 7 — they use exactly the API this guide describes.

Render headlessly

For screenshots, documentation, or automated checks, render without opening a window:

# One headless frame — a quick smoke check.
pixi run py-demos -- --scene rigid_body --headless --frames 1

# Capture a PNG (the helper rejects blank frames and prints the artifact path).
pixi run py-demo-capture -- --scene rigid_body --frames 2 --width 640 --height 360

Headless rendering uses the same render path as the interactive viewer, so a capture is faithful evidence of what the scene looks like.

The standalone viewer

DART also provides a standalone viewer application for source builds:

pixi run dartsim

How visuals relate to physics

DART keeps physics and visuals as separate concerns: the world owns the dynamics, and the viewer reads each body’s world transform to draw it. That separation is why a headless physics-only script (like Hello, DART) needs no graphics at all, while the same world can be handed to the viewer when you want to watch it. You can always inspect a body visually and verify it numerically with body.translation — the two agree because they read the same state.

Next

Ready to go deeper? See Next steps for advanced topics, runnable examples, and the API reference.