Incremental PCB trace simplification for tscircuit. Takes existing high-density routes and optimizes their vias and paths while accounting for obstacles, connectivity, and other routed copper.

TraceSimplificationSolver runs two passes through this pipeline by default:

1. Via removal — remove unnecessary layer transitions.
2. Crossing via reduction — coordinate layer swaps at crossings to remove via pairs (opt-in).
3. Same-net via merging — merge redundant vias belonging to the same net.
4. Path simplification — simplify route geometry, with optional vertex shortcuts.

The solver can run to completion with solve() or advance incrementally with step().

bun add @tscircuit/trace-simplification-solver circuit-json-to-connectivity-map

The package exports TypeScript source. Use Bun or a toolchain that supports TypeScript dependencies.

import {
  TraceSimplificationSolver,
  type HighDensityRoute,
} from "@tscircuit/trace-simplification-solver"
import { ConnectivityMap } from "circuit-json-to-connectivity-map"

const hdRoutes: HighDensityRoute[] = [
  {
    connectionName: "signal",
    traceThickness: 0.15,
    viaDiameter: 0.3,
    route: [
      { x: -2, y: 0, z: 0 },
      { x: -1, y: 1, z: 0 },
      { x: 1, y: 1, z: 0 },
      { x: 2, y: 0, z: 0 },
    ],
    vias: [],
  },
]

const solver = new TraceSimplificationSolver({
  hdRoutes,
  obstacles: [],
  connMap: new ConnectivityMap({}),
  colorMap: { signal: "orange" },
  defaultViaDiameter: 0.3,
  layerCount: 2,
})

solver.solve()
if (solver.failed) {
  throw new Error(solver.error ?? "Trace simplification failed")
}

const simplifiedRoutes = solver.simplifiedHdRoutes
console.log(simplifiedRoutes)

Route points use integer z layer indices: 0 is the top layer, and layerCount - 1 is the bottom layer. Represent a via with consecutive route points at the same x/y on different layers and an entry in vias. Keep coordinates, trace widths, via diameters, and clearances in consistent units (millimeters for tscircuit boards).

For connected routes and pads, populate connMap with their shared identities, for example connMap.addConnections([["signal", "signal_branch", "pad_id"]]). The empty map above is sufficient for the isolated route in the example.

The exported TraceSimplificationSolverOptions type describes the constructor options.

To change the number of pipeline passes, set solver.MAX_SIMPLIFICATION_PIPELINE_LOOPS before solving. This is separate from the step limit, solver.MAX_ITERATIONS.

Instead of calling solve(), call step() until the solver finishes:

while (!solver.solved && !solver.failed) {
  solver.step()
  // Render solver.visualize() here to inspect the current phase.
}

if (solver.failed) {
  throw new Error(solver.error ?? "Trace simplification failed")
}

solver.visualize() returns a GraphicsObject compatible with graphics-debug, both during solving and after completion. The tests include SVG rendering and snapshot examples.

The package also exports UselessViaRemovalSolver, SameNetViaMergerSolver, CrossingViaReductionSolver, and MultiSimplifiedPathSolver for running individual phases. Their constructor options and result accessors differ; see their implementations in lib/solvers and the complete exports in index.ts.

CI uses Bun 1.3.8.

git clone https://github.com/tscircuit/trace-simplification-solver.git
cd trace-simplification-solver
bun install
bun run test
bun run typecheck
bun run format:check

Tests cover via removal, merging, crossing reduction, clearance checks, endpoint preservation, immutable routes, and SVG snapshots.

MIT