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AutoCAD Civil 3D Developer Center

AutoCAD® Civil 3D® is a powerful civil engineering tool incorporating a dynamic engineering model that allows elements to be automatically updated in response to changes in your design. Using AutoCAD® Civil 3D® as a platform, you can take advantage of industry-standard development tools and technologies when building applications.


Learn more about the latest AutoCAD Civil 3D features at the AutoCAD Civil 3D product center.


There are three APIs available for customizing AutoCAD® Civil 3D®:

  • .NET API allows you to write plug-ins to AutoCAD® Civil 3D® in any .NET language.
  • COM API can be used in creating VBA macros which you can run from the AutoCAD Civil 3D command line. Visual Basic for Applications (VBA) IDE is not included by default in AutoCAD® Civil 3D®, but you can download it from You can also create clients that access the COM API from managed (.NET) or unmanaged (C++) code.
  • Custom Draw API (in C++) is an extension of the AutoCAD ObjectARX API that allows you to customize the way AutoCAD® Civil 3D® renders objects. The AutoCAD .NET Overrule API can be used for AutoCAD Civil 3D® objects.
  • Blogs

    The Infrastructure Modeling DevBlog from ADN Team is a useful resource for software developers working with Autodesk Infrastructure Modeling technologies.

  • Public discussion groups provide an open forum for sharing knowledge and receiving support. Join the AutoCAD Civil 3D Developer Discussion Group. You may also find useful software development information in AutoCAD customization discussion groups.

  • Easily extend the power of AutoCAD Civil 3D using apps created for the end user community.

  • Get easy access to Forge APIs and documentation, tutorials, GitHub samples, support and more for Autodesk cloud-based software and components in your own web and mobile applications.

  • Learning

    Because AutoCAD® Civil 3D® is based on AutoCAD®, you can take advantage of all the AutoCAD® source code samples for .NET that are included with the installation of AutoCAD® Civil 3D® software in the Samples directory. There are also additional AutoCAD Civil 3D® specific samples included in the installation.

    • DevTV: Introduction to AutoCAD Civil 3D .NET Programming
      A self-paced video tutorial on how to start developing for AutoCAD Civil 3D with VB.NET. Download
    • Video : AutoCAD Civil 3D 2012 Surface .NET API
      A self-paced video tutorial demonstrating the new Surface objects and related function in AutoCAD .NET API. Download


AutoCAD Civil 3D API documentations is designed for developers who want to customize AutoCAD® Civil 3D® or create applications using the underlying APIs. The Developer’s Guide show how to create code with .NET API and legacy COM API, with explanations and sample codes. The .NET API Reference Guide contains a complete list of objects available.


Although AutoCAD® Civil 3D® does not expose an ObjectARX API, applications built with the AutoCAD ObjectARX SDK or the AutoCAD Map ObjectARX SDK will run within AutoCAD® Civil 3D®. Find out more details about the Tools and programming environments supported for customization and application development of AutoCAD Civil 3D referring to Civil 3D Developers Guide and API Reference Documents.

  • This tool allows developers inspect the Civil3D Database without writing code. It works by showing the root objects of Civil3D (i.e. Styles, Alignments, Corridors, Assemblies, Subassemblies, Pipe networks and Surfaces) listing them on the left with all objects on each collections, such as all alignments on the active drawing, and once click on each item, list all its properties on right.

    To use this tool, follow the instructions at this blog post.