Grasshopper TypeInitializationException

Grasshopper
1

When I load Grasshopper, seemingly since updating to the latest Rhino release yesterday, I’m getting this error:

Priority: ModelContentEnablerLoader
{
  The type initializer for 'Grasshopper.Rhinoceros.Model.ModelInstanceDefinition' threw an exception.
  TypeInitializationException
}

Digging into it a bit, I found that if I reference geometry in Rhino, the Model Object component also throws this error. If I internalize the geometry to the Geometry Parameter, the error goes away.

image
image1920×660 46.2 KB

This has definitely stumped me and is making definitions that worked just fine yesterday no longer able to compute.

System Info:
Rhino 8 SR18 2025-4-10 (Rhino 8, 8.18.25100.11001, Git hash:master @ 5d157e876c23ece334d9c8666b8513ffc6d4a98d)
License type: Commercial, build 2025-04-10
License details: Cloud Zoo

Windows 11 (10.0.26100 SR0.0) or greater (Physical RAM: 32GB)
.NET 8.0.11

Computer platform: DESKTOP

Standard graphics configuration.
Primary display and OpenGL: NVIDIA RTX A2000 (NVidia) Memory: 6GB, Driver date: 4-12-2025 (M-D-Y). OpenGL Ver: 4.6.0 NVIDIA 576.02
> Accelerated graphics device with 4 adapter port(s)
- Windows Main Display attached to adapter port #0
- Secondary monitor attached to adapter port #1

OpenGL Settings
Safe mode: Off
Use accelerated hardware modes: On
GPU Tessellation is: On
Redraw scene when viewports are exposed: On
Graphics level being used: OpenGL 4.6 (primary GPU’s maximum)

Anti-alias mode: 8x
Mip Map Filtering: Linear
Anisotropic Filtering Mode: High

Vendor Name: NVIDIA Corporation
Render version: 4.6
Shading Language: 4.60 NVIDIA
Driver Date: 4-12-2025
Driver Version: 32.0.15.7602
Maximum Texture size: 32768 x 32768
Z-Buffer depth: 24 bits
Maximum Viewport size: 32768 x 32768
Total Video Memory: 6138 MB

Rhino plugins that do not ship with Rhino

Rhino plugins that ship with Rhino
C:\Program Files\Rhino 8\Plug-ins\Commands.rhp “Commands” 8.18.25100.11001
C:\Program Files\Rhino 8\Plug-ins\rdk.rhp “Renderer Development Kit”
C:\Program Files\Rhino 8\Plug-ins\RhinoRenderCycles.rhp “Rhino Render” 8.18.25100.11001
C:\Program Files\Rhino 8\Plug-ins\rdk_etoui.rhp “RDK_EtoUI” 8.18.25100.11001
C:\Program Files\Rhino 8\Plug-ins\NamedSnapshots.rhp “Snapshots”
C:\Program Files\Rhino 8\Plug-ins\MeshCommands.rhp “MeshCommands” 8.18.25100.11001
C:\Program Files\Rhino 8\Plug-ins\IronPython\RhinoDLR_Python.rhp “IronPython” 8.18.25100.11001
C:\Program Files\Rhino 8\Plug-ins\RhinoCycles.rhp “RhinoCycles” 8.18.25100.11001
C:\Program Files\Rhino 8\Plug-ins\Grasshopper\GrasshopperPlugin.rhp “Grasshopper” 8.18.25100.11001
C:\Program Files\Rhino 8\Plug-ins\Toolbars\Toolbars.rhp “Toolbars” 8.18.25100.11001
C:\Program Files\Rhino 8\Plug-ins\Displacement.rhp “Displacement”

2

Update: After running _Reset and “Restore default Rhino application settings,” the errors have been resolved. Still unsure of the culprit.

3

Update 2: After some digging, I found that the issue is with my custom display modes.

I had 3 custom display modes called “[DWG] Shaded”, “[DWG] Technical”, and “[DWG] Technical w/ Hidden”. I’ve found that when I remove the brackets from their names, the error goes away.

I don’t know enough about Rhino’s structure to know why Grasshopper is having an issue with the names of display modes having these characters, but with the names changed, the problem is effectively solved.

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