loopcut

What it does

• The technical work, in a sentence. Rename by material, sort into collections, fix normals, stack modifiers in the right order, wire constraints and drivers, unwrap and pack, build a light rig, set up render presets, batch export. Each of these is one message.
• Every step on screen. The code for each step waits for your approval before it runs (or you tell it to stop asking for this conversation). Its result is measured from the scene, not from what the model printed, so a "Scene changes" card lists exactly what was added, removed and changed.
• It looks at its work. The agent captures the viewport to check itself, and can put a reference photo you dropped on the panel next to a capture to compare and adjust.
• One click back. Every turn that changes the scene is a checkpoint. Undo all restores the scene and the conversation to before it. Your .blend is never written to; a restore lands in place, with the file still yours.
• It knows the scene. File, mode, selection and objects ride with every message, so "make this shinier" works. Type @Name to point at an object, material or collection. Installed add-ons are in its view, and it can use them.
• Your model or ours. Bring a key from Anthropic or any OpenAI-compatible provider, run a model on your own GPU, or sign in for hosted models with nothing to set up.
• It's Blender. Loopcut is Blender 5.2 with a panel and about forty changed files. Import your settings, add-ons, keymap and themes on first launch and carry on. It updates itself.

Install

Grab the latest build from the releases page or loopcut.org/download.

The builds are not yet signed, so the first launch needs one extra click:

• macOS says it "could not verify" Loopcut. Click Done, then System Settings → Privacy & Security → Open Anyway. Or, in Terminal: xattr -dr com.apple.quarantine /Applications/Loopcut.app.
• Windows shows a SmartScreen warning. More info → Run anyway.

On first launch, choose Import Blender 5.2 Settings to bring over your preferences, add-ons, keymap, themes and startup file, or Start Fresh. Then connect a model and you're in. The panel docks to the right of the 3D viewport; ⌘L (CtrlAltL on Windows) focuses it.

Later updates install from inside the app ("Restart to update") and never trigger the warning again.

Your model or ours

With your own key or a local model, nothing touches our servers. With hosted models, the gateway relays the request and keeps token counts for billing, not prompts or scenes.

What to ask it

Rename everything after what it is, put the lights in their own collection, and set up a three-point rig around the bottle.

Apply scale on everything, fix the flipped normals, and purge orphan data.

Add an IK chain to the legs with pole targets, and mirror the naming to .L/.R.

Match the framing of the reference photo I attached and set up a product-shot render preset at 2048².

Sort the modifier stack so Mirror comes before Subdivision on every mesh in Props.

How a turn works

The model works with a small set of tools, and each one is built to tell the truth about the scene:

Drop images on the panel (or + image) to attach up to six references per message. They are stored beside the conversation, never inside your .blend.

Conversations survive restarts and belong to the file they worked in; History lists the others, New chat starts fresh. Long sessions stay affordable: older steps are folded, and the model summarizes when needed, so the context shown in the footer stays within budget.

Loopcut keeps a text log of each conversation for 90 days to fix problems and improve the app: no images, .blend files or keys, and never used for training. Turn it off with Share conversations to improve Loopcut in Preferences › Add-ons › Loopcut › Privacy and Support, where Report a Problem… sends us a note (and, if you like, your latest conversations) and gives you a code to quote.

Building from source

Loopcut is a fork of Blender 5.2.2 on the main branch. The add-on lives in scripts/addons_core/loopcut/ and hot-reloads; the fork adds an editor type, in-place snapshot restore, a separate settings folder, and its own name and icons.

make update                       # fetches Blender's libraries from projects.blender.org
ninja -C ../build/lite install    # the dev build; the same command re-copies the add-on after Python-only changes
python3 -m unittest discover -s loopcut/tests

The developer guide covers the layout, the dev loop, the harness and eval suite, releases, and how checkpoints, conversations and context management work inside.

Contributing

Issues and pull requests are welcome. The fast loop is loopcut/scripts/dev.sh (Blender stays open, saving a file reloads the panel) and python3 -m unittest discover -s loopcut/tests runs without Blender. The Blender-free tests run on every push.

Bundled add-ons

Loopcut includes unmodified, optional System extensions, disabled until needed: UniV by Oxicid (GPL-3.0-or-later); LoopTools by Bart Crouch and Vladimir Spivak, maintained by the community (GPL-2.0-or-later); Node Arrange maintained by Leonardo Pike-Excell (GPL-3.0-or-later, with NetworkX under BSD-3-Clause); MPFB maintained by Joel Palmius and the MakeHuman community (code GPL-3.0-or-later; included assets CC0 1.0; additional asset packs are not bundled); and Bool Tool maintained by Nika Kutsniashvili, with its upstream contributors (GPL-3.0-or-later). Full credits and pinned versions are in bundled.json, with licence texts and the shipped Python sources in the System repository. These packages contain no compiled c