IFC Language Support for VS Code

This extension adds language support for IFC STEP files (.ifc, .step, .stp) in Visual Studio Code and is powered by the IFC Language Server.

For normal use, install the extension and open an IFC file. The extension automatically installs the language server version pinned by the current extension release.

It combines local editor support with the IFC Language Server to provide:

• Syntax highlighting
• Bracket matching and colored bracket pairs
• Diagnostics
• Hover information
• Go to definition
• Find references
• Semantic tokens
• 3D preview of individual elements

Installation

No manual language-server setup is required for normal use.

Install from a .vsix Release

Prebuilt .vsix packages are available on the GitHub releases page:

https://github.com/NepomukWolf/vscode-ifc/releases

To install the extension from a release:

1. Open the releases page.
2. Download the latest .vsix file from the release assets.
3. Open VS Code.
4. Press Ctrl+Shift+P (Cmd+Shift+P on macOS) to open the Command Palette.
5. Search for Install from VSIX and select Extensions: Install from VSIX....
6. Choose the downloaded .vsix file.
7. Reload VS Code if prompted.

Features

Hover Preview for Step IDs

Hover over STEP identifiers such as #12345 to preview their definitions.

IFC Entity Documentation on Hover

Hover over IFC entity names such as IFCWALL to view schema documentation.

Diagnostics

The language server validates IFC entities and attribute values directly in the editor against the correct IFC schema.

It reports issues such as invalid references, wrong primitive value types, unknown entity names, and invalid enumeration values, incorrect cardinalities.

Go to Definition

Use F12 or Ctrl/Cmd-click on STEP identifiers such as #12345 to jump directly to their definitions.

Find All References

Use Shift + F12 to locate all references to an entity.

Syntax Highlighting

Clean syntax highlighting for IFC STEP files.

3D Element Preview

Render any IFC element in 3D without leaving the editor. Place the cursor on an element (or use the Preview in 3D CodeLens above any element with geometry) and run IFC: Preview Element in 3D. A side panel renders that element and its assembly children; orbit, zoom, and click geometry to jump back to its source line.

Rather than loading the whole model, the extension extracts just the selected element's reference closure into a tiny sub-model, so a single element renders quickly even from very large federated files. Geometry is produced by web-ifc and drawn with three.js.

After installation, open an IFC file and the extension will automatically download the required IFC language server.

Usage

1. Open an IFC file (.ifc, .step, or .stp) in Visual Studio Code.
2. Review diagnostics directly in the editor and Problems view.
3. Hover over STEP IDs such as #12345 or IFC entity names such as IFCWALL.
4. Use F12 or Ctrl/Cmd-click for go to definition.
5. Use Shift + F12 for find references.

Settings

Most users do not need to change anything. Advanced settings are available for development and troubleshooting:

• ifc.server.path: Absolute path to a custom IFC language server binary.
• ifc.server.args: Extra command-line arguments passed to the server.
• ifc.server.versionOverride: Advanced override for the Git tag to download instead of the extension-pinned version.
• ifc.server.githubRepository: GitHub repository used for IFC language server downloads, in owner/repo form.
• ifc.server.downloadAssetPattern: Optional substring used to narrow the selected release asset.
• ifc.schema.overwriteExpSchemaWithLocal: Absolute path to a local .exp schema file to force for diagnostics and hover.
• ifc.schema.addLocalSchemaToSelection: List of local .exp files or directories containing .exp files that the language server may use for schema selection.
• ifc.analysis.astFileSizeLimitMb: Maximum file size in MiB for AST-backed language-server features. Larger files keep basic hover, navigation, and semantic tokens available, but skip schema diagnostics and derived-value hover.
• ifc.semanticTokens.enabled: Enable range-based semantic tokens provided by the language server.
• ifc.trace.server: Trace level for the VS Code language client.
• ifc.viewer.includeChildren: Include an element's decomposition/assembly children in the 3D preview.
• ifc.viewer.codeLens: Show the Preview in 3D CodeLens above any element that has geometry (follows the viewport on large files).
• ifc.viewer.maxFileSizeMb: Maximum IFC file size the 3D preview will index to extract an element.

Changes to IFC settings restart the language server automatically.

Commands

• IFC: Download Language Server
• IFC: Restart Language Server
• IFC: Show Resolved Language Server
• IFC: Preview Element in 3D

Editor Configuration

For IFC files, the extension enables these defaults:

• editor.colorDecorators: disabled
• editor.matchBrackets: always
• editor.bracketPairColorization.enabled: enabled

You can override these in your own VS Code settings if desired.

Development

Running the Extension

npm install
npm run compile

Then open src/extension.ts, press F5, and choose VS Code Extension Development Host. A new VS Code window will open.

Alternatively, you can package the extension as a .vsix and install it locally:

npm run package

This creates a .vsix file. In VS Code, press Ctrl+Shift+P (Cmd+Shift+P on macOS), search for Install from VSIX, and choose the generated .vsix file.

Using a Local Language Server Build

If you are developing the language server itself, point the extension at a local build with:

{
  "ifc.server.path": "/absolute/path/to/ifc-language-server"
}

The easiest place to set this while testing is the Extension Development Host's settings JSON.

Using Local .exp Schemas

The extension passes local schema settings to the IFC Language Server through LSP initialization options.

{
  "ifc.schema.overwriteExpSchemaWithLocal": "/absolute/path/to/IFC4x2.exp",
  "ifc.analysis.astFileSizeLimitMb": 128,
  "ifc.semanticTokens.enabled": true,
  "ifc.schema.addLocalSchemaToSelection": [
    "/absolute/path/to/IFC4x1.exp",
    "/absolute/path/to/custom-schemas"
  ]
}

Use ifc.schema.overwriteExpSchemaWithLocal to force one schema. Use ifc.schema.addLocalSchemaToSelection to add individual .exp files or directories to the server's schema lookup pool.

Language Server

This extension is powered by the IFC Language Server.

For normal use, the extension automatically installs the language server version pinned by the current extension release.

For release packaging, the extension expects platform-specific GitHub release assets whose names include operating-system and architecture hints such as macos-arm64, linux-x64, or windows-x64. Supported asset formats are raw executables, .zip, .tar.gz, and .tgz. Archives should contain either ifc-language-server or ifc-lsp, with .exe on Windows.

License

This project is licensed under the MIT License. See LICENSE for details.