Combine Meshes

You've got a head, a torso, and limbs as separate meshes, and you want them treated as one object - for a single export, a single decimate pass, or a boolean against a shared tool. That's Combine Meshes. It takes up to four TRIMESH inputs and merges them into one mesh, right in the graph, no round-trip through a DCC tool.

The important thing to understand is what "combine" means here. This is a merge, not a union. The geometry is concatenated - vertices and faces get pooled into one object - but overlapping parts stay overlapping. If you want overlapping parts carved into one solid, that's the Boolean node's job (union), not this one. Combine is the cheap, instant operation: put four body parts together and then decimate or re-UV them as a single unit.

The inputs that matter

• mesh_a - required. This is the anchor; the combined output carries A's position as the reference frame.
• mesh_b, mesh_c, mesh_d - all optional. Only plug in what you have; a lone mesh_a with nothing else just passes through.

Outputs are combined_mesh (the merged TRIMESH - wire it into a viewer, a saver, or whatever processing node comes next) and info (a STRING with the post-merge stats, handy for catching dropped geometry). Everything speaks GeometryPack's TRIMESH type, so the inputs come from its loaders and the output feeds its viewers, savers, and processing nodes.

Installing it

Same pack, same steps as every node in this pack:

cd ComfyUI/custom_nodes
git clone https://github.com/PozzettiAndrea/ComfyUI-GeometryPack.git
cd ComfyUI-GeometryPack
pip install -r requirements.txt --upgrade
python install.py

Then restart ComfyUI. Or let ComfyUI Manager do it - search "GeometryPack" (or install via Git URL with https://github.com/PozzettiAndrea/ComfyUI-GeometryPack.git). Heads up: the pack's one-click installer is experimental and pulls in the pixi package manager via comfy-env; the README's manual path is the reliable one. It's a young, fast-moving pack, so expect occasional breakage and keep it updated.

Where people get caught

Two recurring confusions. First, people plug meshes into Combine expecting a boolean union and wonder why the inside is still there - read the paragraph above again. Second, four fixed slots run out fast. If you're merging an arbitrary list of meshes - say, a batch of scanned fragments, or every part in a scene - this node's fixed wiring is the wrong tool. Use the batch sibling, Combine Meshes (Batch), which takes a whole list of TRIMESH inputs and merges them in one shot. That's the node that scales; this one is for the quick "I have three or four things" case. Also worth knowing: if your separate parts have inconsistent scales or coordinate spaces, the merged result inherits that mess - combine meshes don't fix transforms, they just host them.