Simulation

Force-directed layout on the GPU. Space toggles it. Four sliders control the physics — repulsion, friction, link spring, and the edges-to-keep percentage.

Force simulation is what turns random node positions into something you can reason about. In a sentence: every node repels every other node (that spreads the graph out), connected nodes pull toward each other (that forms clusters), and friction stops the bouncing (that lets the layout settle). Fast enough that a 1M-node graph lays out in under 30 seconds on a laptop.

Controls

Control	What it does
Space (or Run/Stop)	Toggle simulation
Repulsion	Force pushing every pair of nodes apart. Higher = more spread, weaker clusters.
Friction	Momentum damping. Higher = settles faster, nodes travel less.
Link spring	Pull between connected nodes. Higher = tighter clusters.
Edges to keep %	Drop the bottom (100−X)% of edges by weight for this run. Speeds the sim and declutters dense graphs.
Always keep strongest per node	Guarantees no node is left without its strongest edge when the % slider is low. Keeps the graph connected.
Restart	Re-randomise positions and start over.

The camera auto-follows while the sim is running — the whole graph stays on screen as it reshapes.

What “settled” looks like

A laid-out graph has three visual cues:

1. Clusters separate. If your data has community structure, you’ll see distinct clumps of nodes with mostly internal edges and sparser bridges between.
2. Node motion slows to near-zero. Frames-per-second on the sim counter should plateau; visually, nodes stop jittering.
3. No “piling” at the edges. If nodes compress into a ring at the boundary, your graph is too big for the simulation space — reduce repulsion, or see Limits if you’re above ~1M nodes.

For a 1k-node clustered graph, settling takes 3–5s. For 100k, 15–20s. For 1M, 25–40s. Past that see Limits.

Tuning recipe

Most graphs look right at default settings. When they don’t, the pattern matches the problem:

Graph looks tangled, nodes bunched in the middle

1. Raise repulsion (wider spread)
2. Lower friction (nodes travel further before settling)
3. Let it run longer — complex layouts need 20–30 seconds

Graph collapses into a solid ball

1. Lower repulsion — too much is as bad as too little
2. Raise friction to kill the bouncing
3. Lower link spring — connected nodes are winning the tug-of-war

Dense edges obscure the structure

1. Lower edges to keep % to 20–40% for the layout run
2. Tick always keep strongest per node so the graph doesn’t fragment
3. Once settled, raise edges-to-keep back to 100% to see the full network around the positioned nodes

Disconnected components drift apart forever

The default force model has no global gravity. Small disconnected components will float off indefinitely. Accept it (they’re disconnected — that’s informative) or pre-filter to the largest component before loading.

Gotchas

• Running the simulation past ~2M nodes drops interaction framerate noticeably. Pre-filter with the Filter panel first.
• Restart re-randomises positions — your current layout is gone. Export first if you want to preserve it.
• Rotation is disabled while the sim is running — it would immediately overwrite the rotated positions. Hit Space to stop, rotate, then resume.
• Re-opening an exported graph loads the saved positions, but pressing Space still starts a fresh simulation that will reshape them. Hit Stop immediately if you only wanted to view the saved layout.
• On older hardware (old integrated GPUs, some Chromebooks) the simulation space can shrink below the usual size; you’ll see a console warning and the graph may feel cramped. See Limits.