OriginalCircuit.Altium

A high-performance .NET library for reading and writing Altium Designer EDA files without requiring Altium Designer to be installed. It supports schematic libraries, PCB libraries, schematic documents, and PCB documents, and provides cross-platform rendering to raster images and SVG.

This is version 2.0 — a complete rewrite of the original AltiumSharp library with a new async API, source-generated serialization, and cross-platform rendering.

Supported File Types

File Type	Extension	Read	Write	Render
PCB Library	.PcbLib	Yes	Yes	Yes
Schematic Library	.SchLib	Yes	Yes	Yes
Schematic Document	.SchDoc	Yes	Yes	Yes
PCB Document	.PcbDoc	Yes	Yes	Yes

Installation

Install the core library:

dotnet add package OriginalCircuit.Altium

Optional rendering packages:

dotnet add package OriginalCircuit.Altium.Rendering.Raster   # PNG/JPG via SkiaSharp
dotnet add package OriginalCircuit.Altium.Rendering.Svg      # Vector SVG output

Quick Start

Reading a schematic library:

using OriginalCircuit.Altium;

await using var reader = new SchLibReader("MyLibrary.SchLib");
SchLib schLib = await reader.ReadAsync();

foreach (SchComponent component in schLib.Components)
{
    Console.WriteLine($"{component.Name}: {component.Description}");
}

Reading a PCB library:

await using var reader = new PcbLibReader("MyFootprints.PcbLib");
PcbLib pcbLib = await reader.ReadAsync();

foreach (PcbComponent component in pcbLib.Components)
{
    Console.WriteLine($"{component.Name} — {component.Primitives.Count} primitives");
}

Creating a new PCB library:

using OriginalCircuit.Altium;
using OriginalCircuit.Altium.Records;
using OriginalCircuit.Altium.BasicTypes;

var pcbLib = new PcbLib();
var component = new PcbComponent { Name = "R0402" };

component.Primitives.Add(new PcbPad
{
    Location = new CoordPoint(Coord.FromMils(-25), Coord.Zero),
    SizeTop = new CoordPoint(Coord.FromMMs(0.56), Coord.FromMMs(0.62)),
});

pcbLib.Components.Add(component);

await using var writer = new PcbLibWriter("Output.PcbLib");
await writer.WriteAsync(pcbLib);

Rendering

Three rendering packages are available, all built on the abstractions in OriginalCircuit.Altium.Rendering.Core:

• OriginalCircuit.Altium.Rendering.Raster — renders to PNG or JPG using SkiaSharp (cross-platform)
• OriginalCircuit.Altium.Rendering.Svg — renders to SVG using .NET XML APIs (no native dependencies)

Both renderers draw individual components (PcbComponent, SchComponent) and whole documents (PcbDocument boards and SchDocument sheets):

var board = await new PcbDocReader().ReadAsync("board.PcbDoc");

await new RasterRenderer().RenderAsync(board, "top.png",
    new RenderOptions { Width = 2000, Height = 2000 });

PCB board views and layers

Board renders fill the physical board outline as a black substrate — so copper, silk and solder mask read like a real board and the outline stands out — and accept an optional PcbRenderSettings for the view side and layer visibility:

// Flipped bottom view (mirrored so it reads as if the board were turned over),
// with mechanical and internal-copper layers hidden for a clean read of the routing.
var settings = new PcbRenderSettings
{
    ViewSide = PcbViewSide.Bottom,   // Top | Bottom | Both
    ShowMechanical = false,          // hide mechanical layers (57-72)
    ShowInternalCopper = false,      // hide mid-signal layers (2-31) and planes (39-54)
    // Or take full control instead of the toggles:
    // LayerFilter = layer => PcbLayerGroups.IsSignalOrSilk(layer),
};

await new RasterRenderer().RenderAsync(board, "bottom.png", options, settings);

PcbLayerGroups classifies layer IDs (IsCopper, IsOverlay, IsMechanical, IsInternalPlane, IsMultiLayer, IsSignalOrSilk) for building custom LayerFilter predicates. Component designator/comment text honours each component's visibility flags, and inverted (knockout) silk labels render as filled rectangles.

See the examples/ directory for complete rendering examples.

Examples

The examples/ directory contains runnable examples, each with its own walkthrough README. The guides index lists them by topic.

• CreateFiles — create SchLib and PcbLib files from scratch
• LoadFiles — read files and inspect their contents
• ModifyFiles — read a file, modify components, and write it back
• RenderFiles — render components and boards to PNG and SVG (with board view-side and layer options)
• ExtractBom — read a schematic and produce a grouped bill of materials (CSV + HTML)
• GeneratePickAndPlace — read a board and write an assembly pick-and-place (centroid) CSV
• ExtractEmbeddedAssets — extract embedded 3D STEP models and images to disk
• InspectBoard — report a board's outline size, layer stack, counts, and design rules
• NetReport — count the copper objects on each net
• BuildFootprintGenerator — generate parametric QFN/DIP footprints into a PcbLib
• BuildMultiPartComponent — build a multi-part symbol with PartCount / OwnerPartId
• LibraryCatalog — render a whole library to a PNG/SVG thumbnail gallery
• WalkHierarchy — walk a hierarchical schematic through its sheet symbols
• DiffLibraries — report added/removed/changed components between two libraries
• ValidateLibrary — surface reader diagnostics plus library-hygiene lint
• WebPreviewService — render component previews to an HTTP response (minimal API)

Run any example with:

dotnet run --project examples/CreateFiles

Read-oriented examples load a file from TestData/ by default, or take a path to your own file:

dotnet run --project examples/ExtractBom -- "C:\path\to\MyBoard.SchDoc"

Credits

This library is a rewrite of the original AltiumSharp project. Original implementation by Tiago Trinidad (@Kronal).

License

MIT — see LICENSE for details.