FreeCAD 是一款免費、開放原始碼的參數化 3D CAD 建模軟體，主要用於工程製圖和產品設計，但也適合工程方面更廣泛的用途，如建築或其他工程專業。
這款功能導向的軟體提供與 Catia、SolidWorks 或 Solid Edge 相似的建模工具，所以亦被歸類為 MCAD、PLM、CAx 和 CAE 軟體。它也是一款具備模組化軟體架構的參數化建模工具，所以能在不必修改核心系統的情況下提供額外的功能。
與現代許多 3D CAD 建模軟體一樣，FreeCAD 也有許多 2D 元件，可以描繪 2D 形狀或自 3D 模型取出詳細的設計資料來建立 2D 生產製圖，但直接的 2D 製圖 (如 AutoCAD LT) 並非重點所在，而動畫或有機形狀 (如 Maya, 3ds Max, Blender 或 Cinema 4D) 也不是。不過，由於這款軟體具有廣泛的適用性，它的用途可能比目前的主要用途還要寬廣許多。
這款軟體大量使用科學運算領域所有龐大的開放原始碼程式庫，包括強大的 CAD 核心 OpenCascade、Open Inventor 主要程式 Coin3D、世界知名的使用者介面架構 Qt 以及目前最佳的腳本語言 (scripting language) 之一的 Python。FreeCAD 亦可被其他程式用作程式庫。
這款軟體也是跨平台的，目前可以毫無瑕疵地在 Windows、Linux/Unix 和 Mac OSX 系統中運作，而在所有平台的介面和功能完全一樣。
注意：程式啟動後為英文介面，請從 Edit → Preferences → General → Language 中選擇 Chinese Traditional，按下 OK 後，即變成繁體中文介面。
§ 作業系統：Windows XP/Vista/7/8
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FreeCAD 原文簡介：
FreeCAD is a general purpose parametric 3D CAD modeler. The development is completely Open Source (LGPL License). It is aimed directly at mechanical engineering and product design but also fits in a wider range of uses around engineering, such as architecture or other engineering specialties.
The program features tools similar to Catia, SolidWorks or Solid Edge, and therefore also falls into the category of MCAD, PLM, CAx and CAE. It is a feature based parametric modeler with a modular software architecture which makes it easy to provide additional functionality without modifying the core system.
As with many modern 3D CAD modelers it has many 2D components in order to sketch 2D shapes or extract design detail from the 3D model to create 2D production drawings, but direct 2D drawing (like AutoCAD LT) is not the focus, neither are animation or organic shapes (like Maya, 3ds Max, Blender or Cinema 4D), although, thanks to its wide adaptability, it might become useful in a much broader area than its current focus.
The program makes heavy use of all the great open-source libraries that exist out there in the field of Scientific Computing. Among them are OpenCascade, a powerful CAD kernel, Coin3D, an incarnation of Open Inventor, Qt, the world-famous UI framework, and Python, one of the best scripting languages available. The software itself can also be used as a library by other programs.
The program is also fully multi-platform, and currently runs flawlessly on Windows and Linux/Unix and Mac OSX systems, with the exact same look and functionality on all platforms.