Using mathematical optimization, tris to quads.
- Download https://github.com/SaitoTsutomu/Tris-Quads-Ex/archive/refs/heads/master.zip
- Start Blender.
- Edit menu -> Preferences
- Select the "Add-ons" tab.
- Press the "Install ...".
- Select the downloaded ZIP file and press the button "Install Add-on".
- Check the "Mesh: Tris to Quads Ex".
This add-on needs PuLP.
- on macOS
/Applications/Blender.app/Contents/Resources/3.6/python/bin/python3.10 -m pip install pulp
- on Windows
"C:\Program Files\Blender Foundation\Blender 3.6\3.6\python\bin\python" -m pip install pulp
- Select an object.
- Turn to the edit mode.
- Select the edges.
- Select "Tris to Quads Ex" of the face menu.
Triangular faces are converted to square faces as possible.