RIR Grasshopper Error

Rhino.Inside Revit
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1

Hi

I cannot load Grasshopper in Revit…

I can open Rhino from Revit but not GH…(I tried to uninstall and Install again RIR…but nothing changed…I currently use Rhino8 and Revit2025… I’m also a Tekla user…and Tekla 2025 works ok)

I got this error…

An error occured during GHA assembly loading:
Path: C:\ProgramData\Autodesk\Revit\Addins\2025\RhinoInside.Revit\R8\RhinoInside.Revit.GH.gha
Exception System.MissingMethodException:
Message: Method not found: ‘System.Drawing.Bitmap Grasshopper.Kernel.IGH_ObjectProxy.get_Icon()’.

2

Hi Ric,

What exact Rhino 8 version & Revit are you running?

This sounds like a plugin conflict. Revit 2025.3 and above ships with a plugin manager for trouble shooting.

If you are on the latest of everything, try uninstall RiR and reinstall.

3

Hi

I have the same problem.

I have used RIR in this morning. After finishing one project, opening up a nem Revit, this ERROR showed up.
I have deleted RIR, reinstalled, deleted everything with a special program that could connect to RIR. After this move Revit did not start… So deleted Revit and reinstalled it as well.

Now I have reinstalled the latest REVIT(25), RHINO8, RIR. Still not working.

GH starts anyway, but RIR components can not load in.

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4

You are having plugins conflicts. Lets isolate from Revit addin and 3rd party plugins.

Revit 2025.3 and above ships with an Addin Manager that allows you can temporarily disable addins.

In Rhino you can disable via Properties/Plugins.

Grasshopper can be loaded via the Rhino command line with GrasshopperLoadOneByOne and say No to 3rd party plugins. Or uninstall via package manager/move the plugins out of the gh folder.

5

Hi @Balázs_Emri1,

It looks like you have Wombat installed twice.
I updated Grasshopper on Rhino 8.32 to be more robust on these cases.
But it will not be available as RC until May 12th.

6

(additional information:
Rhino version:Version 8 SR30
(8.30.26103.11001, 2026-04-13)
Revit:25.4.50.35
20260410_1515(x64)
2025.4.5)

@Japhy

Revit Addin Manager (already restarted, so its up to date)

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In Rhino Plugin manager I did not disable anything

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BUT I did “GrasshopperLoadOneByOne” command, and now there was not an ERROR

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Based on this, it should be a plugin conlfict as you said.
Now how could I figure out, which plugin is the problem?(I have several, so testing out 1by1 should be a “z” plan.)

@kike I deleted the duplicated Wombat.

(Thanks for your help already!)

7

SOLVED!

  1. Purged out nearly every components.
  2. Copied back one component at a time.
  3. Started Revit..RIR to see if it works
    4…repeat(2. & 3.) until it fails.

In my case IdeaStatica component caused the problem. So I deleted, now it looks like RIR works fine.
(I have not tried to download a fresh IdeaStatica component and see if it interrupt again or not.)

8

Is that their Revit or Rhino plugin? or both?

9

It is their Rhino plugin.

10

Revit 2025 is in netcore 8, they probably have that plugin targeting 4.8 (works in pre-2025 versions)