Using Inventor 2027 Built-In Addin Dependency Isolation

Autodesk Inventor, working with .NET Framework, previously allowed add-ins to use NuGet package/assembly versions that differed from those bundled with Inventor. However, with Autodesk Inventor 2025-2026 and the framework upgrade to .NET 8, this no longer worked out of the box and caused version conflicts. Autodesk recently released Inventor 2027, using .NET 10, with built-in assembly isolation to address this.

This article shows how to use that built-in isolation, using AssemblyLoadContext, to load an add-in and its dependencies into a separate container and avoid version clashes

A full sample application is available on GitHub. This repo combines the workflows for Inventor 2023-2024 (.NET Framework 4.8), Inventor 2025–2026 (.NET 8), and Inventor 2027 (.NET 10 with built-in isolation)

What is AssemblyLoadContext?

• It's the runtime's provider for locating and loading dependencies. Whenever a dependency is loaded, an AssemblyLoadContext instance is invoked to locate it.

• AssemblyLoadContext provides a service of locating, loading, and caching managed assemblies and other dependencies.

• To support dynamic code loading and unloading, it creates an isolated context for loading code and its dependencies in their own AssemblyLoadContext instance.

How to update the add-in?

Update Addin (.addin) File

• Add the <UseInventorAssemblyContext> property set to 0 (zero).

<?xml version="1.0" encoding="utf-8"?>
<Addin Type="Standard">
	<ClassId>{YOUR-GUID-HERE}</ClassId>
	<ClientId>{YOUR-GUID-HERE}</ClientId>

	<DisplayName>IsolatedInventorAddin</DisplayName>
	<Description>IsolatedInventorAddin</Description>

	<Assembly>IsolatedInventorAddin.dll</Assembly>

	<!--Created for Autodesk Inventor 2027+, version 31.0-->
	<SupportedSoftwareVersionGreaterThan>30..</SupportedSoftwareVersionGreaterThan>
	<LoadOnStartUp>1</LoadOnStartUp>
	<Hidden>0</Hidden>

	<UseInventorAssemblyContext>0</UseInventorAssemblyContext>
</Addin>

Notes

• The <UseInventorAssemblyContext> property is backwards compatible, as it is ignored and does not break when included in earlier Inventor versions.

• With the change to <Addin Type="Plugin">, this add-in format is compatible and works as an AppBundle with the Automation API.

References

• TylerWarner.dev Blog - Isolated Autodesk Addins Series

• Microsoft Learn - System.Runtime.Loader.AssemblyLoadContext

• GitHub - dotnet - AssemblyLoadContext.md

• Autodesk Inventor Documentation - Creating An Inventor Add-In