Mesh Decimate

Not to be confused with Blender's Decimate modifier (a non-destructive, whole-object effect) - Mesh Decimate is the direct edit-mode operator version, sometimes called "Decimate Geometry": it collapses the currently selected vertices/edges/faces down toward a target ratio, permanently reducing polygon count on just the selection you fed it, rather than the whole mesh through a modifier stack.

How it works

This wraps Blender's mesh.decimate operator. Working only on what's selected means you can be surgical - heavily simplify a dense, generated region of a mesh (say, the interior of a segmented layer that doesn't need fine detail) while leaving hand-tuned or visually important geometry elsewhere on the same object untouched. It supports vertex-group weighting so decimation strength can vary across the selection instead of applying uniformly, and an optional symmetry constraint to keep the result mirrored across an axis rather than collapsing unevenly on each side.

The inputs and outputs that matter

• BPY_OBJ - the mesh, with the geometry you want decimated already selected.
• ratio (default 1, range 0–1) - how much geometry survives. 1 means no change; push it down toward 0 for more aggressive collapsing. This is the parameter that actually does the work.
• use_vertex_group (default false) plus vertex_group_factor (default 1) and invert_vertex_group (default false) - lets a vertex group's weights bias how much decimation each part of the selection gets, rather than applying ratio uniformly everywhere.
• use_symmetry (default false) with symmetry_axis (X, Y, or Z) - keeps the decimation result mirrored across the chosen axis, useful for symmetric character meshes where an uneven collapse would look obviously wrong.

Output is a single BPY_OBJ, the same mesh with the selected geometry decimated in place.

How to install it

ComfyUI Manager, search "Avatar Graph" and install, or manually:

cd ComfyUI/custom_nodes
git clone https://github.com/avatechai/avatar-graph-comfyui

then pip install -r requirements.txt and restart. Needs Blender's bpy module, pinned to Python 3.10.x - a dedicated conda environment on macOS/Linux, or Avatech's prebuilt Python-3.10 ComfyUI zip on Windows with the pack installed through Manager afterward.

Common issues & troubleshooting

If nothing gets simplified, check selection first - this operates only on selected geometry, so an empty selection going in means an unchanged mesh coming out, regardless of what ratio is set to.

If the result looks lopsided or broken on what should be a symmetric character mesh, use_symmetry is off by default - turn it on and set the correct symmetry_axis for your mesh's orientation before assuming the decimation algorithm itself is the problem.

A bpy import failure at startup is the pack's Python-version pin, not this node - confirm a clean Python 3.10.x environment with requirements.txt installed without errors. And if you were actually after a non-destructive, whole-object reduction you can dial in later rather than a permanent edit on a selection, that's the Decimate modifier, which this operator-based node isn't - the two share a name but not a workflow.