CoatLink

A small, predictable two-way model bridge between Blender and 3D-Coat. Models only: no baking, no texture nodes, no scene surgery.

_{The CoatLink menu in Blender's top bar  ·  the CoatLink panel in 3D-Coat. Both carry the same sections in the same order.}

• one CoatLink button in Blender's top bar and one panel in 3D-Coat - both carry the same sections in the same order with the same words
• Send / Pull in both directions. Objects keep their names, their materials and their place in the outliner; nothing in your scene is renamed, joined or deleted
• units and axes are read from 3D-Coat itself, so 2 m in Blender is 2 m in 3D-Coat
• optional voxel remesh on send (over the exported copy only), and one-click To voxels in 3D-Coat that converts what the Sculpt Tree is showing

1. Download coat_bridge.zip from the latest release.
2. In Blender: Edit > Preferences > Add-ons > ▾ (top right) > Install from Disk… and pick that zip (Blender 4.2 and newer).
3. Enable CoatLink in the add-on list, then press Detect in its menu.

Download CoatLink-Setup.cmd and double-click it. It fetches the installer from the latest release, runs it with the Python 3D-Coat itself ships, and keeps the window open so you can read what it did. Nothing to unzip, no console, no path to edit. If 3D-Coat sits under C:\Program Files the button icons need administrator rights, so it asks Windows for elevation once and runs the installer again: that single prompt is the whole privilege story, and without it everything except the icons still installs. The file is short enough to read before you run it.

Already have the release unzipped? install.cmd does the same thing from the files in front of it. It finds both folders on its own, writes the menu entries with your paths, clears out anything an older layout left behind, and is harmless to run twice.

Both folders are worked out on the spot, wherever 3D-Coat is: the program folder comes from the uninstall entries Windows keeps, and its data folder follows your Documents folder - which is where it is not once Documents is redirected to OneDrive. 3D-Coat from a folder of your own, on any drive, works too.

Already in the Scripts > Show Python console? Paste this one line - it needs no download either (the console is on 3D-Coat's own Python):

import urllib.request; exec(urllib.request.urlopen("https://github.com/VictoryLuode/Blender-CoatLink/releases/latest/download/CoatLink-Setup.py").read().decode())

With git-bash, MSYS or WSL, ./install.sh does the 3D-Coat half too. PowerShell does both halves in one go:

.\install.ps1

If Windows refuses to run scripts, start it explicitly - normal and safe for a script you just downloaded and read:

powershell -NoProfile -ExecutionPolicy Bypass -File .\install.ps1

Every door runs the same installer (coat_side/CoatLinkInstall.py): the .cmd and the console line only fetch it. A test installs with each door into a throwaway tree and compares the results file by file, so they cannot drift apart.

Then restart 3D-Coat and look for Scripts > CoatLink. Three tool buttons also appear at the end of the Sculpt and Paint tool lists. To take it all back out: install.cmd --uninstall (or .\install.ps1 -Uninstall, ./install.sh --uninstall, python CoatLinkInstall.py --uninstall) - it removes its own files and nothing else.

Copying the files by hand, explicit install paths and the XML 3D-Coat needs: docs/install.md.

1. Scope picks the selected object (default) or every visible one. Import as picks how 3D-Coat opens it - Sculpt Object (voxel) by default. Remesh on send can voxel-remesh the exported copy only; the scene, the names and your own modifiers stay as they are.
2. Send. If 3D-Coat is not running, the job waits in the exchange folder until it is - Start 3D-Coat is right there in the menu.
3. Work in 3D-Coat, then File > Export To > BlenderBridge (or Bring object back). With Auto receive on, the model is imported within ~2 s and merged into the object it came from: same name, same materials, same place in the outliner, new geometry.

From the 3D-Coat side, Send hands over the node selected in the Sculpt Tree plus its children (Scope: whole scene uses 3D-Coat's own export instead - the only route that can carry textures), and To voxels converts everything the tree is showing. It does that by pressing 3D-Coat's own S/V badge - the conversion you would do by hand - and accepts the dialog for you, so a scene converts from one click.

What every entry does, on both sides: docs/menus.md.

One exchange folder, one file layout, one vocabulary:

<3D-Coat exchange root>/
    import.txt                 the job: what to load, where to return, how to open it
    BlenderBridge/             our folder - everything else lives in here
        bridge.obj             the model, both directions (one axis rule, one unit rule)
        export.txt             written by 3D-Coat when it hands a model back
        pull-history.json      what was already imported, so a restart does not repeat it
    CoatLink_AfterImport.py    run after the import: drops 3D-Coat's wrapper node

Nothing else is written, and only files inside a BlenderBridge folder are ever touched - which is what lets 3D-Coat's official AppLink stay enabled. Measurements, the two exchange roots and the differences from the official AppLink: docs/protocol.md.

Blender 4.2+ (developed on 5.2 LTS) · 3D-Coat 4.8.15+ (tested against 2025/2026) · Windows for the installers and the test scripts; the Blender add-on itself is OS-independent and 3D-Coat ships the Python its half needs.

Stated plainly, because a bridge that quietly does half the job is worse than one that says so:

• The [vox] import mode is asked for, not guaranteed. 3D-Coat's own log shows it reading that line, but on the build this was developed against the model still arrives in surface mode (S in the Sculpt Tree). To voxels in the panel is the reliable route; the cause has not been identified.
• No live round trip has been run on this release. Both suites run headless against a stand-in host; tests/live_roundtrip.sh exists for a real one and records the exact job file it wrote, which is the evidence the earlier attempts were missing.
• The reduction percentage is an estimate, and To voxels accepts the conversion dialog's defaults - so one object cannot be skipped mid-run.
• Button icons need an elevated run when 3D-Coat lives under C:\Program Files; without it the buttons simply use their default icons, and the installer reports that.
• 3D-Coat's "whole scene" export is 3D-Coat's own, so what it covers is its decision.

The full list, including what is deliberately not shipped: docs/limitations.md.

tests/run_tests.sh                                   # Blender side, headless
coat_side/tests/run_tests.sh                         # 3D-Coat side, stand-in host
tests/test_coat_export.sh path/to/real-export.obj     # the return leg on a file 3D-Coat wrote
tests/live_roundtrip.sh 900                           # the real thing: both apps open

No 3D-Coat and no Blender GUI are needed for the suites: the Blender tests drive throwaway script and exchange folders, and the 3D-Coat tests run against a stand-in coat module on 3D-Coat's own Python. The scripts pick the newest Blender build and 3D-Coat's bundled Python themselves; BLENDER=, COAT_PYTHON= and COAT_DIR= override.

Current counts: Blender main suite 196/196 plus every regression script and both installer smoke tests; 3D-Coat logic 160/160, tools 29/29, tree report 12/12, installer checks, API stub check, idle-redraw check and probe dry run.

GPL-3.0-or-later, see LICENSE. Copyright (C) 2026 VictoryLuode.