Optimize scene "Transmission" not found in blender 4.0

[TheDuckCow]

The most common error report we have in the current version of MCprep is below, only affected blender 4.0+ users (90 different users have submitted reports). This appears to be only present in v3.5.1 of the addon

Raw report:

File "<addon_path>/prep.py", line 292, in execute\n bpy.ops.mcprep.optimize_scene()\n File "<addon_path>/ops.py", line 109, in __call__\n ret = _op_call(self.idname_py(), kw)\nRuntimeError: Error: Python: Traceback (most recent call last):\n File "<addon_path>/optimize_scene.py", line 325, in execute\n self.is_pricipled(context, mat_type, node)\n File "<addon_path>/optimize_scene.py", line 183, in is_pricipled\n transmission_socket = node.inputs["Transmission"]\nKeyError: 'bpy_prop_collection[key]: key "Transmission" not found'\nLocation: C:\Program Files\Blender Foundation\Blender 4.0\4.0\scripts\modules\bpy\ops.py:109\n\n

Different associated user messages with this report (quotes):

• Prepping JMC materials
• Hola quiero comunicar este error. Este me paso por que intente hacer una animacion, le di a la opcion el renderizado de siclos de ecenas. y me salto este error
  • My Spanish is not that great, and google translate gets hung up on 'siclos', but I gather it's the same root as above with an issue on optimizing the scene.
• prepping materials
• i was trying to optimize my scene in cycles for faster renderng

[StandingPadAnimations]

Hola quiero comunicar este error. Este me paso por que intente hacer una animacion, le di a la opcion el renderizado de siclos de ecenas. y me salto este error

Using my best Spanish translating ability (Texas forces us to take 2 years of learning a language other then English for graduation), though this will be more of a general translation, and will be far from perfect:

Hello, I want to communicate this error. I came across this when I try to make an animation, with the render option "Optimize Cycles Scene", and I get this error

("Siclos" I assume means "Cycles" in this context, from the phrase "siclos de ecenas", which I assume means "Cycles scene")

That out the way, I'm not exactly sure what's going on, but I have been wanting to remove the Cycles optimizer for a while now, for several reasons:

• Hasn't caught up with latest Cycles developments
• Algorithm is extremely buggy at times; there's been cases of it setting max bounces to values like 80. Ironically, I don't even use the optimizer (despite making it) for this very reason, and opt to manually optimize my scene
• Better tools exist for automatic optimization; the Super Image Denoiser devs at Pidgeon Tools have SFR, a Cycles optimizer that actually profiles the scene, making it far better then what we have.
• While the intent of the MCprep optimizer was to have something tuned specifically for Minecraft animation, I feel that over time, that became "how do we optimize a scene while not profiling, due to the average user's hardware?"

However, I'm open to other ideas regarding how we move forward the optimizer

[TheDuckCow]

Thanks for weighing in. I do agree that unless we have solid benchmarking in place to legitimize the choices made, it does seem a bit arbitrary. That being said, removing in a minor patch would be a bit hasty, so I'd prefer we try and fix whatever this narrow reference bug is, even if the rest of the alog is left the same for this.

[StandingPadAnimations]

Alright, I'll mark the optimizer as deprecated, and slate it for removal in MCprep 3.6

[TheDuckCow]

FYI I'm working on the fix now for this.