Object Set Use Mesh Mirror Z

Of the three mesh-mirror flags in Avatar Graph, Object Set Use Mesh Mirror Z is the one with the smallest audience. X mirrors left/right - the axis your avatar actually cares about. Y mirrors front/back - occasionally useful, usually not for characters. Z mirrors top/bottom, and a character whose head is mirrored onto its feet is a character you've made a mistake with. But it exists, it's cheap to understand, and understanding it is the same as understanding the whole ObjectSet_ family.

What it actually does

In Blender's edit mode, the X/Y/Z mirror toggles make every mesh edit duplicate symmetrically across that axis. use_mesh_mirror_z is the Z toggle: edits to the top half of the mesh get mirrored onto the bottom half. That's genuinely handy for objects that are vertically symmetric - containers, pillars, some props - and genuinely wrong for anything with a distinct top and bottom, which is every character you'll rig with this pack. It defaults to false, and that default is load-bearing.

The reason it's here at all is structural, not practical: Avatar Graph auto-generates one ObjectSet_ node for every simple attribute on Blender's object type (the full list is in the pack's blender/ops_mesh.py), then wraps each in a setter that does setattr(object, name, value) and hands the object back. No hand-filtering, no "is this useful for avatars?" check. That's why you get three mirror flags, six ray-visibility flags, and a sculpting flag in a rigging pack. It's the price of unfiltered Blender access, and honestly it's a fair price.

The inputs and outputs that matter

• BPY_OBJ - the mesh whose mirror flag you're setting.
• value - boolean, default false. true turns on Z-axis mirror editing.

Output is the same BPY_OBJ, flowing on to whatever Blender node comes next.

How to install it

Ships with the whole Avatar Graph pack - ComfyUI Manager, search "Avatar Graph", or:

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

restart ComfyUI. The pack-wide install snag: bpy==3.6.0 only has wheels for Python 3.10.x, so the pip install fails on newer Python. Use a python=3.10 conda env (Linux/macOS) or Avatech's prebuilt Python-3.10 ComfyUI zip (Windows).

Gotchas

Real talk: the only way this node "goes wrong" is if you turn it on for a character, because then your head edits start duplicating onto the feet. If that's happening, that's this flag - turn it off. Like its siblings it's inert outside Blender's edit mode, so a generate-and-rig pipeline will never see it do anything, which is fine and expected.