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Fill & Join

BEGINNER
📖2 min read
Fill & Join

Introduction​

"Fill" and "Join" are often confused, but they serve distinct purposes in modeling. Fill creates new geometry (edges or faces) to close gaps, while Join (Connect Vertex Path) cuts existing faces to create new edges between vertices.

Resources

Access guides on filling holes and merging objects.

Links

Explore Blender's Fill and Join operations.

Videos

Watch tutorials on mesh repair and object management.

Fill (F)​

The F key is context-sensitive and creates geometry based on your selection:

  • 2 Vertices Selected: Creates an Edge connecting them.
  • 3+ Vertices Selected: Creates a Face (Polygon) connecting them.
  • Closed Edge Loop Selected: Creates a generic N-gon face filling the hole.

Grid Fill​

For filling large holes with clean, quad-based topology (instead of one giant N-gon), use Grid Fill (Face > Grid Fill).

  • Requirement: The boundary loop must have an even number of vertices.

Join / Connect Vertex Path (J)​

The J key connects two selected vertices with an edge that cuts through the existing face.

  • Why not use F? If you select two vertices on a face and press F, you create a floating edge on top of the face (bad topology). If you press J, you split the face properly.

Join Objects (Ctrl + J)​

In Object Mode, Ctrl + J merges multiple selected objects into a single mesh object. This is different from the edit mode tools above.

Summary​

  • F (Fill): Creates new geometry to bridge gaps.
  • J (Connect): Cuts existing faces to connect vertices.
  • Ctrl + J (Join Objects): Merges separate objects.

Documentation for Methodology​

What to document when Filling and Joining

In Your Method Section​

Mention if you had to manually repair holes in scanned data or photogrammetry models.

In Your Decision Log​

Record the following when using this technique:

  • Reason for filling (e.g., "Capping the cylinder" or "Repairing a hole in the scan")
  • Use of Grid Fill vs. standard Fill (topology quality)

Verification​

After using F to create large faces, check that the resulting N-gons don't cause shading errors. If using J, ensure the cut didn't create extremely thin triangles.

Example Methodology Statement​

"Holes in the photogrammetry mesh were identified and closed using the Fill tool (F). Large openings were closed with Grid Fill to maintain quad topology for subsequent sculpting."