Mesh Split

Easy to confuse with Mesh Separate, and worth being precise about the difference up front. This node wraps Blender's real bpy.ops.mesh.split operator, part of Avatar Graph, the pack that runs actual Blender inside ComfyUI's process (via the bpy Python package) to build interactive 2D-to-3D avatars, auto-generating a node for every mesh operator Blender has.

How it works, and how it's different from Separate

Split duplicates the vertices along the boundary of your current selection and detaches that selection from its neighbors - the shared vertices at the edge get doubled up, so the selected piece is no longer connected to the rest of the mesh through those points. Mesh Separate goes a step further and pulls the disconnected piece out into a whole new object; Split just breaks the connection and leaves everything inside the same mesh, now sitting as disconnected islands within one object. It's the lighter-weight version - useful as a prep step before something that needs disconnected geometry without necessarily needing separate objects yet, or before a subsequent LOOSE-mode Separate.

Inputs and output

The only input is BPY_OBJ - the mesh coming in, with a selection already established upstream marking the boundary you want to break. Nothing else to configure.

Output is a single BPY_OBJ, geometry now disconnected at that boundary.

Where it's actually useful

Anywhere you want one region of a mesh to stop influencing its neighbor through shared geometry - before a Solidify or extrude step you want applied to one island without it dragging the connected piece next to it along for the ride, or as a setup step ahead of a LOOSE-type Separate once you've deliberately carved out the boundary you want split off.

Installing it

ComfyUI Manager: search "avatar-graph-comfyui", install, restart. Manually: cd ComfyUI/custom_nodes && git clone https://github.com/avatechai/avatar-graph-comfyui, then cd avatar-graph-comfyui && python -m pip install -r requirements.txt, then restart.

Python 3.10.x is the requirement to nail down first - the bpy package this pack is built on needs that exact minor version, and the README recommends a dedicated conda environment on macOS/Linux (conda create --name comfyui python=3.10) rather than trusting an existing Python install. Windows users get a prebuilt ComfyUI + Python 3.10 zip linked in the README to unzip over their install before adding the pack via Manager - worth double-checking this step carefully, since at least one ComfyUI Desktop user has reported this pack's install going sideways in a more dramatic way than a typical dependency error (an oversized logo taking over the UI plus a stray audio dialog after installing through Manager), which points more at Desktop-specific install quirks than anything wrong with your mesh graph itself. Restart with --enable-cors-header (macOS also wants --force-fp16) for the live 3D preview.

Common issues

Rule out the Python version first if this pack's nodes aren't loading. On this node itself: with nothing selected, it's a silent no-op - no error, just nothing to split. If a downstream Solidify or extrude step is behaving as though geometry is still connected across a boundary you meant to break apart, that's the thing to check - Split needs to run on a real, deliberate selection boundary between the piece you want isolated and everything around it, not just anywhere near it.