LIGHTTABLE

LIGHTTABLE is a local-first browser workbench for reading, inspecting, measuring, marking up, lightly editing, and re-exporting printed circuit board manufacturing data.

It is built for engineers, fabricators, technicians, hardware developers, and makers who need a fast way to examine board files without uploading them to a remote service or installing a desktop computer-aided manufacturing suite.

Current release: v1.5.2
License: GPL-3.0
Standalone runtime dependencies: None
Telemetry: None

Why LIGHTTABLE?

PCB manufacturing packages are often a mixture of Gerber, drill, placement, native design, drawing, and archive formats. LIGHTTABLE brings those files into one browser-based instrument with an explicit fidelity model:

• Local-first: imported files stay in the browser.
• Offline-capable: the complete instrument is one self-contained HTML file.
• Format-aware: supported, approximated, and refused constructs are disclosed.
• Manufacturing-conscious: sensitive exports are withheld unless their validation gates pass.
• Source-preserving: supported native edits patch the smallest possible source fields and retain unknown content.
• Responsive: expensive connectivity analysis runs on demand in a cancellable Web Worker.
• Review-friendly: calibrated 2D inspection and an interactive geometry-derived 3D view share the same parsed board model.

LIGHTTABLE is not a replacement for the original electronic design automation system, a fabrication sign-off process, or a source-certified mechanical model. It is an inspection and evidence instrument.

Quick start

Run the standalone instrument

1. Download or clone this repository.
2. Open public/lighttable.html in a current desktop browser.
3. Drop in board files, select a folder, choose a ZIP or TGZ package, or load the included sample.

No installation, server, build process, account, CDN, remote font, or network connection is required.

Deploy to any static host

Copy public/lighttable.html to the desired web directory and rename it index.html.

For example, to publish at:

https://example.com/projects/lighttable/

place the file at:

/projects/lighttable/index.html

The release ZIP follows this layout and can be extracted directly into a static folder.

Run the repository site wrapper

The repository includes a small Vinext wrapper used to publish the standalone instrument as a full-screen hosted application.

Requirements:

• Node.js 22.13 or newer
• npm

npm run install:ci
npm run dev

For a production validation build:

npm test
npm run lint
npm run benchmark:lighttable

Primary workflow

INTAKE -> RENDER -> INSPECT -> MARK / EDIT -> OUTPUT

1. Intake: choose files, a directory, or a supported archive.
2. Render: inspect layers in calibrated 2D or the geometry-derived 3D review view.
3. Inspect: measure, search, trace named nets, or explicitly analyze derived connectivity.
4. Mark or edit: add separate review markup or perform only the native edits supported by the source format.
5. Output: export review evidence, preserving native files, or validated manufacturing packages when the fidelity tier permits it.

Major capabilities

Board inspection

• Layered 2D canvas with top and bottom views
• Pan, zoom, fit, palette presets, layer visibility, color, and opacity controls
• Resizable board workspace with device-local layout persistence
• Feature selection, board statistics, component and net search
• Snapped point distance and feature-boundary clearance measurement
• Explicit and connected-geometry board outline detection
• PNG, composite PDF, per-layer vector PDF, and print outputs

Interactive 3D review

• Dependency-free software projection using the same parsed board geometry as 2D
• Orbit, pan, wheel zoom, and isometric, top, and bottom presets
• Persistent Top and Bottom canvas controls that refit the requested 3D side, plus automatic migration of stale camera state after renderer upgrades
• Assembled top and bottom surfaces that hide reverse-side artwork and clip every visible feature to the detected board profile
• PCB material mapping for solder mask, exposed copper, off-white silkscreen, plated holes, board edges, and dark component packages
• Board extrusion, projected drills, and approximate component bodies
• Adjustable board thickness, component height, visibility, and exploded layer spacing
• Component and pad selection with a path back to precise 2D inspection
• Deterministic scene limits for predictable performance on larger jobs

At zero layer separation, the 3D view presents the camera-facing assembled surface. Adding separation deliberately switches to a diagnostic fabrication stack with both sides visible. The 3D view is an orientation and review model. Precise measurement, editing, 1:1 printing, and manufacturing decisions remain in the calibrated 2D view.

Connectivity analysis

• On-demand geometry-derived networks
• Same-layer copper contact and plated-hole bridges
• Reconciliation of source-net names with derived networks
• Open named-net, source-net conflict, and dangling endpoint detection
• Network tracing and JSON or CSV evidence export
• Cancellable background processing with live progress
• Geometry-revision caching that rejects stale results after real edits

Connectivity is physical evidence derived from supported geometry. It does not reconstruct schematic intent.

Preserving edits and validated output

• Minimal source-field patches for supported KiCad, Eagle, DXF, and ODB++ transforms
• Diff preview before native write-back
• Unknown-token and unedited-source retention
• Mandatory production-parser reopen validation
• Gerber export with preserved aperture definitions and X2 attributes
• Automatic Gerber re-import and geometry comparison at 0.01 mm
• Separate plated and non-plated Excellon output
• Validated ODB++ ZIP and TGZ output
• Human-readable and machine-readable round-trip evidence

Format support

Format	Intake	Native edits	Output	Fidelity
Gerber RS-274X / X2	Common lines, arcs, flashes, regions, macros, repeats, polarity, and X2 attributes	Board-model edits	Re-import-certified Gerber	Full or Partial
Excellon / XNC	Drills, plating, G85 slots, routed slots, units, and zero suppression	Board-model edits	Separate PTH and NPTH drill files	Full or Partial
Gerber job file	Layer ordering metadata	No	Generated job manifest	Full or Partial
KiCad .kicad_pcb	Selected footprints, pads, segments, and text	Supported move, rotate, and mirror transforms	Preserving native write-back after reopen validation	Partial
Altium .PcbDoc	Read-only ASCII and bounded binary CFB intake	No	Review evidence only	Partial or Preview
Eagle .brd / .eagle	XML layers, signals, packages, elements, and common package geometry	Element move, 90-degree rotate, and side mirror	Preserving XML write-back after reopen validation	Partial
ASCII DXF .dxf	Common 2D entities, units, and native layers	Move, rotate, mirror, and delete for supported shapes	Preserving native output or double-reimport-certified generated DXF	Partial
ODB++ folder, ZIP, TGZ, or TAR.GZ	Common v7 and v8 text trees	Narrow feature and standalone component transforms	Validated preserving ZIP or TGZ	Partial
Placement CSV	Common column layouts	Board-model edits	Placement CSV	Full or Partial
ZIP, TAR, or GZIP	Bounded local extraction	No	Format-dependent	Container only
IPC-2581, IPC-D-356, BoardView	Not available	No	No	Planned

Support is intentionally conservative. A recognized file extension does not imply complete semantic coverage.

Fidelity model

Every loaded board receives one of three visible fidelity tiers:

Tier	Meaning
Full	No known loss exists in the recognized elements.
Partial	Unsupported, retained, or approximated elements are named in the Fidelity Report.
Preview	The board is suitable only for orientation. Measurement and manufacturing output are locked.

The fabrication package includes FIDELITY.txt, ROUNDTRIP.txt, and ROUNDTRIP.json where applicable. Preserving native exports keep validation evidence in the interface and expose it separately instead of modifying the original source tree with sidecar files.

Never treat a Full result as a substitute for reviewing the exported files in the source electronic design automation or computer-aided manufacturing system.

Output types

Depending on source format and fidelity, LIGHTTABLE can produce:

• PNG review image
• Composite review PDF
• Per-layer vector PDF package with title blocks and a 50 mm print-check bar
• Browser print view with a 100 mm verification bar
• Placement CSV
• Markup JSON package
• Connectivity JSON and CSV evidence
• Fidelity report
• Preserving KiCad, Eagle, DXF, or ODB++ output
• Certified Gerber, drill, and job ZIP package

The interface hides or locks outputs that are unsafe for the active source.

Local data and security model

LIGHTTABLE has no runtime network dependency and does not transmit imported board data.

Device-local persistence uses IndexedDB for the active board, annotations, edits, layout settings, selected display mode, and 3D camera state. Use Fresh Start to clear the active local session.

All imported content is treated as untrusted. The parsers enforce limits for:

• archive member count and expanded size
• compression ratio and nested containers
• unsafe, absolute, traversal, and duplicate paths
• ZIP CRC and TAR header checksums
• Gerber tokens, features, repeats, apertures, and coordinates
• Excellon tools, records, features, and coordinates
• ODB++ records, member sizes, coordinates, and generated TAR size
• Altium CFB sectors, allocation chains, directories, streams, cycles, and record lengths

Imported text is never evaluated as executable code. Displayed source strings are escaped.

Important limitations

• Curves used for snapping and boundary clearance are tessellated to a declared 0.01 mm tolerance.
• Connectivity considers supported copper contact and plated-hole geometry, not electrical intent.
• Clear-polarity geometry is excluded as a conductor, but its voids are not yet fully boolean-subtracted during connectivity analysis.
• Browser print scaling must be verified against the included physical scale bar.
• Native editing is deliberately narrow and format-specific. Unsupported objects remain read-only.
• Altium support is read-only. Embedded models, advanced pad stacks, design rules, polygon repour, cavities, and unverified stream families are not fully interpreted.
• The 3D view does not interpret STEP models or embedded Altium 3D bodies. Board stack, materials, mask openings, plated barrels, package shapes, heights, and clearance envelopes remain approximate.
• 3D scenes are bounded to 20,000 visible source features, 3,000 drilled features, and 2,000 component bodies. Larger jobs use deterministic sampling and disclose it.
• Archive intake is bounded to 200 members, 25 MiB per input file, and 80 MiB expanded. Generated TGZ output is limited to a 32 MiB expanded TAR.
• Folder selection and native compression support vary by browser.

See TESTING.md for the complete hostile-input and release criteria.

Performance and quality gates

The v1.5.2 release includes:

• 146 in-app parser, archive, geometry, connectivity, native-write-back, camera-recovery, and 3D assertions
• 29 project-level tests
• A generated-worker execution gate
• A 6,000-feature inspection, connectivity, and 3D benchmark
• A 10,000-record Altium ASCII intake benchmark

Gate	Release limit
Immediate Inspect path	Less than 100 ms
Connectivity core, 6,000-feature corpus	Less than 10 s
3D render, 6,000-feature corpus	Less than 250 ms
Altium ASCII intake, 10,000 records	Less than 1 s
Standalone HTML	Less than 350 KiB

Run the automated suite:

npm test
npm run lint
npm run benchmark:lighttable

Run the browser harness from About -> Run self-test.

Architecture

The application is intentionally concentrated in one standalone file:

flowchart TD
    A["Local files or archives"] --> B["Bounded browser parsers"]
    B --> C["Normalized board model"]
    C --> D["Calibrated 2D and review 3D"]
    C --> E["Inspection and connectivity worker"]
    C --> F["Validated exports and local autosave"]

Loading

• public/lighttable.html contains the production interface, parsers, normalized model, renderers, workers, edit plans, validation, and export logic.
• The hosted wrapper renders that same file full-screen, keeping offline and hosted behavior aligned.
• IndexedDB stores only device-local application state.
• Inline Blob-backed Web Workers isolate expensive analysis without adding deploy-time assets.
• No application server, database, login, CDN, telemetry endpoint, or third-party runtime package is required.

Repository layout

Path	Purpose
public/lighttable.html	Complete standalone LIGHTTABLE instrument
app/	Thin hosted application wrapper and metadata
worker/	Cloudflare-compatible site entrypoint
tests/	Project release and regression tests
scripts/lighttable-benchmark.mjs	Large-job performance gates
TESTING.md	Manual checks, hostile corpus, and release criteria
CHANGELOG.md	Version history
BLOG_POST.md	Project launch article
SHA256SUMS	Release checksum for the standalone application
vendor/	Notices for referenced or retained third-party work

Contributing

Contributions should preserve LIGHTTABLE's conservative fidelity contract.

1. Fork the repository and create a focused branch.
2. Make the smallest coherent change.
3. Add parser, hostile-input, round-trip, or performance coverage as appropriate.
4. Run the complete test, lint, and benchmark gates.
5. Update TESTING.md and CHANGELOG.md when behavior or support changes.
6. Open a pull request that describes the input format, expected fidelity, failure behavior, and validation evidence.

Please do not:

• add a runtime network dependency for board processing
• silently reinterpret missing units or malformed coordinates
• claim Full fidelity for an unsupported construct
• unlock manufacturing output for Preview input
• discard unknown native-source content during a supported edit
• include proprietary or customer board files in public issues or fixtures

Synthetic or explicitly redistributable fixtures are preferred.

Specifications and acknowledgements

ODB++ handling follows the common text-tree structures documented in the Siemens ODB++Design Format Specification 8.1 Update 4.

Altium binary intake follows the Microsoft Compound File Binary Format. Verified PcbDoc storage families and primitive framing were cross-checked against the MIT-licensed tscircuit altiumts project. Its notice is retained in vendor/altiumts.LICENSE.md.

Roadmap

The next v1.x targets under hostile review are:

• IPC-D-356 netlist intake
• IPC-2581 review support
• Read-only BoardView preview
• Practical design-for-manufacturability checks
• Panelisation and production-preparation workflows

New format support will remain gated by explicit fidelity reporting, bounded parsers, hostile-input tests, and reopen or round-trip evidence where output is permitted.

License

LIGHTTABLE is licensed under the GNU General Public License v3.0.