LibreCAD — Free Open Source 2D CAD Application

Introduction

LibreCAD is a free, open-source 2D CAD application forked from QCAD Community Edition. It provides a complete set of drafting tools for architects, engineers, and hobbyists who need precise technical drawing without the cost of commercial CAD software.

What LibreCAD Does

• Creates precise 2D technical drawings with lines, arcs, circles, and splines
• Supports layers, blocks, and hatching for organized complex drawings
• Reads and writes DXF and DWG formats for compatibility with AutoCAD
• Provides dimensioning tools for annotating measurements automatically
• Offers snapping, grid, and construction line tools for drafting accuracy

Architecture Overview

LibreCAD is written in C++ using the Qt framework. The drawing engine stores entities (lines, arcs, text, dimensions) in a layered model with coordinate precision up to 16 decimal places. Rendering uses Qt's QPainter with optional OpenGL acceleration for large drawings. The command line at the bottom of the interface accepts typed commands similar to AutoCAD's command-line input model.

Self-Hosting & Configuration

• Available in most Linux distribution repositories
• macOS and Windows installers available from the official website and GitHub
• Configure drawing units (metric or imperial) and default layer settings in Preferences
• Customize the toolbar layout and keyboard shortcuts for your workflow
• Set up pen styles, line widths, and colors for print output

Key Features

• Full DXF and DWG file format support for AutoCAD interoperability
• Command-line input for fast, keyboard-driven drafting
• Comprehensive snap modes including endpoint, midpoint, intersection, and perpendicular
• Block library for reusing common symbols and components
• Print and export to PDF, SVG, and various image formats

Comparison with Similar Tools

• AutoCAD — industry-standard commercial CAD; LibreCAD covers core 2D drafting for free
• FreeCAD — focuses on 3D parametric modeling; LibreCAD is dedicated to 2D drafting
• QCAD — the project LibreCAD forked from; QCAD has a commercial professional edition
• DraftSight — commercial 2D CAD by Dassault; LibreCAD is fully free and open source

FAQ

Q: Can LibreCAD open AutoCAD files? A: Yes. It reads DXF natively and has partial DWG support through the libdxfrw library.

Q: Does LibreCAD support 3D modeling? A: No. It is strictly a 2D drafting tool. For 3D work, consider FreeCAD or Blender.

Q: Is LibreCAD suitable for architectural floor plans? A: Yes. It has all the tools needed for floor plans, including dimensioning, hatching, and layering.

Q: Can I script or automate tasks in LibreCAD? A: LibreCAD has experimental plugin and scripting support, though it is less mature than AutoCAD's LISP.

Sources

• https://github.com/LibreCAD/LibreCAD
• https://librecad.org