How to Use Grid Fill in Blender

The Grid Fill command in Blender is a specialized mesh modeling tool designed to fill closed edge loops with a clean, quad-based grid topology. This article explains what Grid Fill is, the strict geometry requirements needed to run it successfully, step-by-step instructions for using the command, and how to adjust its settings to maintain optimal mesh flow.

What is the Grid Fill Command?

Grid Fill bridges an open boundary or hole in a 3D mesh by generating an interconnected grid of four-sided polygons (quads). Unlike pressing the F key—which creates a single large n-gon or simple flat face—Grid Fill interpolates the surrounding surface curvature and creates clean edge loops that match the surrounding geometry.

Geometry Requirements

To use Grid Fill without receiving an error, your selection must meet specific criteria:

  • Closed Edge Loop: You must select an unbroken loop of boundary edges surrounding a hole.
  • Even Number of Vertices: The total number of selected vertices forming the loop must be an even number (e.g., 8, 12, 16).
  • Balanced Sides: The algorithm logically splits the loop into four sections. It works best when opposing sides of the boundary have an equal vertex count.

How to Execute Grid Fill

  1. Enter Edit Mode (Tab) and switch to Edge Select mode (2).
  2. Select the boundary edge loop surrounding the hole by holding Alt and clicking on one of the edges.
  3. Open the Face Menu by pressing Ctrl + F (or Face in the top viewport menu).
  4. Select Grid Fill from the menu.

Adjusting Grid Fill Parameters

Once executed, open the Adjust Last Operation panel in the bottom-left corner of the viewport (or press F9) to tweak the fill topology:

  • Span: Determines the number of grid lines used to bridge the gap. Adjust this value if the generated faces look stretched or distorted.
  • Offset: Rotates the direction and corner points of the generated grid. Use this setting if the grid lines look twisted or do not line up with the natural edge flow of your mesh.
  • Simple Blending: When enabled, uses a simpler interpolation method that can help prevent vertices from bunching up on organic surfaces.