Registering autodesk.inventor.interop.dll itself with regsvr32 is usually impossible and is not the correct approach. Unlike a typical COM DLL, this interop assembly is a .NET assembly. It must be registered with the .NET Framework tool RegAsm.exe .
For anyone working with the Inventor API, this DLL is not just a component; it's a fundamental requirement. The Interop library completely describes the entire Inventor API in a .NET-friendly way. When a developer writes an add-in, they must add a reference to this DLL in their Visual Studio project. This action makes the thousands of Inventor API objects, methods, and properties available directly in their code.
: Since you are working with COM through an interop layer, remember to properly release objects from memory (using Marshal.ReleaseComObject ) to prevent Inventor processes from "hanging" in the background after your code finishes.
autodesk.inventor.interop.dll is a dynamic link library (DLL) file that plays an essential role in the Windows operating system by enabling modular programming and code reuse. But more specifically, for anyone involved in automating or extending Autodesk Inventor, this file is the critical bridge that allows applications written in .NET languages (such as C# and VB.NET) to communicate with Inventor’s underlying COM (Component Object Model) API. It is the official Interop Assembly provided by Autodesk, often installed with Inventor itself. autodesk.inventor.interop.dll
(Note: Replace with your specific version of Inventor, such as 2024, 2025, or 2026). How to Use the DLL in Visual Studio
in Visual Studio.
or via standard installation folders, making it straightforward to start a project in Visual Studio. Integration Registering autodesk
Right-click in Solution Explorer and select Add Reference .
: C:\Windows\Microsoft.NET\assembly\GAC_MSIL\Autodesk.Inventor.Interop\ . Critical Usage Settings
using Inventor; using System.Runtime.InteropServices; public void ConnectToInventor() try // Try to connect to an active Inventor instance Inventor.Application invApp = (Inventor.Application)Marshal.GetActiveObject("Inventor.Application"); invApp.Visible = true; // Make it visible if it was hidden catch // If not running, start a new instance Type invAppType = Type.GetTypeFromProgID("Inventor.Application"); Inventor.Application invApp = (Inventor.Application)Activator.CreateInstance(invAppType); invApp.Visible = true; Use code with caution. B. Manipulating Documents For anyone working with the Inventor API, this
This comprehensive technical guide explores what this dynamic-link library (DLL) is, how it works under the hood, how to configure it in your development environment, and best practices for building high-performance CAD automation tools. What is autodesk.inventor.interop.dll?
Navigate to the tab (or browse directly to the Inventor installation folder, usually C:\Program Files\Autodesk\Inventor [Version]\Bin ).
using System; using System.Runtime.InteropServices; using Inventor; namespace InventorAutomation class Program static void Main(string[] args) Inventor.Application _invApp = null; try // Attempt to hook into a running instance of Inventor try _invApp = (Inventor.Application)Marshal.GetActiveObject("Inventor.Application"); catch (COMException) // If not running, create a new background process Type invType = Type.GetTypeFromProgID("Inventor.Application"); _invApp = (Inventor.Application)Activator.CreateInstance(invType); _invApp.Visible = true; // Toggle visibility as needed if (_invApp != null) Console.WriteLine($"Successfully connected to: _invApp.SoftwareVersion.DisplayVersion"); // Simple Automation: Count open documents Console.WriteLine($"Active documents: _invApp.Documents.Count"); catch (Exception ex) Console.WriteLine($"Error communicating with Inventor API: ex.Message"); Use code with caution. Critical Development Rules & Pitfalls
: Including this DLL enables IntelliSense in your IDE, which provides autocomplete and documentation for the thousands of methods and properties available in the Inventor API Autodesk Community, Autodesk Forums, Autodesk Forum Why Use It? Complexity
When you write an Inventor add-in, you usually reference the primary Inventor Interop Library via the Autodesk.Inventor.Interop reference in Visual Studio. Behind the scenes, that points to autodesk.inventor.interop.dll .