: Since it relies on a COM interface, it is subject to single-threaded performance constraints typical of the Inventor engine. Efficient design requires minimizing "chatty" calls between the .NET application and the COM server. Stack Overflow Developer Experience Highlights Ease of Use : Readily available as part of the Inventor Add-in Template
Once connected, you can invoke the documents collection to spin up a clean modeling space.
For (Visual Basic for Applications) environments inside Inventor, this DLL is referenced automatically. For external .NET applications (standalone EXEs or Inventor add-ins), you must manually add a reference to this file in your Visual Studio project.
Many beginners set Copy Local = True , thinking it makes the app portable. This is a mistake. The interop DLL relies on the exact Inventor version installed. If you copy it and deploy to a machine with a newer Inventor version, the interop methods may call missing or changed COM interfaces. Always reference the DLL directly from the installed Inventor folder. autodesk.inventor.interop.dll
catch (COMException)
If your application is 64‑bit (recommended for modern Inventor versions), compile your project for x64 . AnyCPU may work but can cause runtime surprises.
Often set to for standalone apps to ensure the DLL is present, but False for Add-ins since the DLL is already in Inventor's memory. Version Compatibility Use older versions : Since it relies on a COM interface,
In this path, 20xx represents the specific version number of Inventor, such as 2023 or 2024. Prior to Inventor 2010, the file was located in an SDK folder, but this Public Assemblies folder has been the standard location for many years.
Developers writing automated regression tests for Inventor features use this DLL to programmatically open files, perform operations, and validate results.
using System; using System.Runtime.InteropServices; using Inventor; namespace InventorAutomation class Program static void Main(string[] args) Inventor.Application inventorApp = null; try // Attempt to connect to an existing, running instance of Inventor inventorApp = (Inventor.Application)Marshal.GetActiveObject("Inventor.Application"); catch (COMException) try // If Inventor isn't running, attempt to start a new instance Type inventorAppType = Type.GetTypeFromProgID("Inventor.Application"); inventorApp = (Inventor.Application)Activator.CreateInstance(inventorAppType); inventorApp.Visible = true; catch (Exception ex) Console.WriteLine("Could not start or connect to Inventor: " + ex.Message); return; // Successfully connected, get the active document if (inventorApp != null && inventorApp.ActiveDocument != null) Document activeDoc = inventorApp.ActiveDocument; Console.WriteLine($"Successfully connected! Active Document: activeDoc.DisplayName"); else Console.WriteLine("Connected to Inventor, but no document is currently open."); Use code with caution. Best Practices for Working with the Interop Library This is a mistake
One of the most frequent user complaints involves a System.IO.FileNotFoundException when using Vault. A typical error message looks like: System.IO.FileNotFoundException: Could not load file or assembly 'Autodesk.Inventor.Interop, Version=...' or one of its dependencies. The system cannot find the file specified. .
Unlike standard .NET objects, COM objects are not managed by the .NET Garbage Collector. If you create hundreds of geometry points or parameters in a loop, they will stay in memory until Inventor closes, leading to massive memory leaks. Explicitly release your objects when finished: