Object Multires Base Apply

Object_MultiresBaseApply is the Blender Multires modifier's "make this my new base" button, exposed as a node. If you've ever worked with a Multires modifier in Blender you know the deal: you've got a base mesh plus a stack of subdivision levels on top, and edits made at a high level can't just be "kept" without deciding what becomes the new base. This node does exactly that - it applies the current level's shape down so it becomes the permanent base for everything above it.

Why it's in an avatar pack

Avatar Graph builds faces and body parts as Blender meshes, and its multi-level workflows (fine detail on top of a low-poly base, sculpted face layers) are exactly where Multires lives. Object_MultiresBaseApply is the auto-generated wrapper for bpy.ops.object.multires_base_apply(). You reach for it when you've reshaped a layer and you want that shape baked in as the base - so later operations start from the shape you actually made, not the original low-poly cage.

How it works

Standard Object_* plumbing: feed in a BPY_OBJ (an object in the shared headless Blender scene), and the node makes it the active object and runs the operator. The only other input is modifier, a plain text field where you type the Multires modifier's exact name - usually Multires, or Multires.001 if there are duplicates.

One thing to keep in mind: this is destructive by nature. Applying the base rewrites the base mesh, so there's no "undo" that a later node can reverse. In practice you want it near the end of a mesh-detail chain, right before the shape flows or export, not in the middle of a pipeline you're still iterating on.

Output is the same BPY_OBJ, so you can keep wiring downstream.

Installing it

It ships in Avatar Graph, so you install the pack:

• ComfyUI Manager: search "Avatar Graph" (repo avatechai/avatar-graph-comfyui), install, restart.
• Or:

cd ComfyUI/custom_nodes
git clone https://github.com/avatechai/avatar-graph-comfyui
cd avatar-graph-comfyui && python -m pip install -r requirements.txt

The pack pins bpy==3.6.0, which only supports Python 3.10 - newer versions fail with "no module named bpy" and the whole pack dies. Windows users get the easiest path from the README: their bundled Python 3.10 zip (ComfyUI_3.10.7z, run run_nvidia_gpu_3.10.bat). Elsewhere, make a python=3.10 conda env.

Gotchas

• Type the modifier name exactly - Multires - or the operator silently does nothing.
• The shared Blender scene resets each graph run (Avatar Main Output triggers it), so the base mesh only exists if an upstream node created it in the same run.
• If you get an error about the modifier not being Multires, you've pointed it at the wrong object. This node only makes sense on objects that actually carry a Multires modifier.