Massive Arnold plugin (massive101_arnold.dll) breaks Arnold Render Settings in Maya 2025–2027 / MtoA 5.6.x

[virtualrepublic]

Prologue

When I opened the Maya Arnold render settings, the Common window was minimized to a smallest size. I had four versions of Maya installed (2024 through 2027). Only version 2024 worked; none of the other versions did.

After some initial research, it turned out that this error had occurred in the past. None of the solutions from various forums worked.

I then systematically tried to find the cause in a discussion with Claude. In the end, I uninstalled all versions of Maya and cleaned up any remaining files. I also uninstalled Redshift. I tested drivers and older versions of Arnold. The error persisted.

This morning, I approached the issue with a fresh perspective and analyzed the error message from the script window that appears when I open the Arnold Render Settings. It turned out there was a conflict with “massive 101”. I then uninstalled “massive 101” and the error was resolved.

The following bug report was generated by Claude from the context window.

Summary

The Massive-to-Arnold bridge plugin `massive101_arnold.dll` fails to load and corrupts Arnold's driver node setup in recent MtoA versions, making the Arnold Render Settings unusable.

Environment

- Massive Arnold plugin: `massive101_arnold.dll`
- Maya 2025.3 / 2026 / 2027 (all affected)
- MtoA 5.6.x (Arnold core bundled with these Maya versions)
- Windows
- Not present with older MtoA (5.5.x / Maya 2024)

Symptoms

- On opening Arnold Render Settings, the Common tab collapses to a few pixels and is unusable. All other tabs (Arnold Renderer, System, AOVs, Diagnostics) build normally.
- Script Editor throws:
```
ValueError: .../mtoa/ui/ae/utils.py line 139: No object matches name: defaultArnoldDriver.callback
RuntimeError: .../mtoa/cmds/rendererCallbacks.py line 663
RuntimeError: .../mtoa/ui/globals/common.py line 747: menuItem: Object 'mayaSoftwareNameDotFrameDotExtension' not found
```
- The "menuItem not found" error is a follow-on; the root exception is the missing `callback` attribute on the Arnold driver node.
- In the Arnold System tab, Render Device is locked to CPU and cannot be switched to GPU (RTX 5090 detected correctly but unselectable).

Root cause

Running `kick.exe -nodes` revealed the bridge failing to load:
```
WARNING | unable to load dynamic library ...\Massive\bin\massive101_arnold.dll
```
The plugin registers its own driver nodes (`massive_ipr_display_driver`, `massive_procedural`) and, when it fails to load against MtoA 5.6.x, leaves the Arnold driver node setup in an inconsistent state — the driver node ends up missing the `callback` attribute MtoA expects, which crashes the Render Settings UI build.

Workaround

Uninstalling Massive (or removing `massive101_arnold.dll` from `ARNOLD_PLUGIN_PATH`) fully resolves the issue.

Request

Please provide a Massive Arnold bridge build compatible with current MtoA 5.6.x / Arnold core (Maya 2025–2027), or document the supported Arnold version range for `massive101_arnold.dll`.

[massive]

The Arnold plugins with Massive 9.3 are compatible with Arnold 7.5.1.0. Massive 101 Arnold rendering works with Arnold standalone. If you would like to run multiple versions of Arnold then it might be best to set environment variables in scripts so that Arnold picks up the appropriate plugins.

[massive]

Here's more detail on how to get Massive 101 and Maya both working:

1 - Simplest solution is to install Maya 2027.1 which includes Arnold 7.5.1.1. This is compatible with the Massive 101 Arnold plugins, so rendering with Arnold works for both Massive 101 and Maya. But this doesn't fix the Arnold Render Settings window. Here's how to fix the Arnold Render Settings window:

- Delete the ARNOLD_PLUGIN_PATH environment variable from system environment variables.
- Run launch_101.bat whenever you want to run Massive 101

Here's what goes into launch_101.bat:

Code: Select all

@echo off
set "ARNOLD_PLUGIN_PATH=C:\Program Files\Massive\bin"
start "" "C:\Program Files\Massive\bin\massive101.exe"

2 - If running a version of Maya older than 2027.1 then Maya will be using an incompatible version of Arnold. For example, Maya 2026.3 includes Arnold 7.4.3.2. Here's how to get Arnold to work for both Maya and Massive 101, and fix the Arnold Render Settings:

- Install Arnold 7.5.1.0 at C:\Program Files\SolidAngle\arnold-7.5.1.0 (Arnold 7.5.1.1 also works)
- Delete the ARNOLD_PLUGIN_PATH environment variable from system environment variables.
- Make sure that only the appropriate Arnold location is in Path (e.g. C:\Program Files\Autodesk\Arnold\Maya2026\bin\ )
- Run launch_101.bat whenever you want to run Massive 101

Here's what goes into launch_101.bat:

Code: Select all

@echo off
set "ARNOLD_PLUGIN_PATH=C:\Program Files\Massive\bin"
set "PATH=C:\Program Files\SolidAngle\arnold-7.5.1.0\bin;%PATH%"
start "" "C:\Program Files\Massive\bin\massive101.exe"

launch_101.bat can be placed in C:\Users\username\bin or anywhere you like to keep batch scripts. It works by setting ARNOLD_PLUGIN_PATH and, for case 2, by prepending the location of Arnold 7.5.1.0 to Path. Neither of these will affect Maya because they are only valid inside the script.