How to Select Faces by Side Count in Blender

Selecting faces based on their polygon side count in Blender is an essential technique for cleaning up 3D geometry, identifying non-quads, and optimizing meshes for rigging or game engines. Blender includes a built-in feature called Select Faces by Sides that allows you to instantly isolate triangles (3-sided), quads (4-sided), or n-gons (5+ sided) across your model. This guide explains how to locate and use this tool efficiently in Edit Mode.

Step-by-Step Guide to Select Faces by Side Count

  1. Enter Edit Mode: Select your mesh in Object Mode and press Tab (or choose Edit Mode from the top-left mode dropdown menu).
  2. Switch to Face Select Mode: Press 3 on your keyboard (not the numpad) or click the Face Select icon in the top-left corner of the 3D Viewport.
  3. Deselect All Geometry: Press Alt + A (or A twice) to clear your current selection so you can clearly see the results.
  4. Open the Tool: In the top menu bar of the 3D Viewport, click Select > Select All by Trait > Select Faces by Sides.

Configuring the Selection Settings

Once you activate the command, an Adjust Last Operation panel will appear in the bottom-left corner of the 3D Viewport (press F9 if it is minimized). Adjust the following settings to target specific face types:

  • Number of Vertices: Enter the target side count (e.g., 3 for triangles, 4 for quads, or 4 when looking for n-gons).
  • Type (Comparison Operator):
    • Not Equal To: Selects all faces that do not match the specified number (e.g., set vertices to 4 to select all triangles and n-gons).
    • Less Than: Selects faces with fewer sides than the target (e.g., set to 4 to pick up only triangles).
    • Equal To: Selects only faces matching the exact side count (e.g., set to 4 for quads only).
    • Greater Than: Selects faces with more sides than the target (e.g., set to 4 to highlight all n-gons with 5 or more sides).

Useful Shortcuts and Preset Applications

  • Finding N-Gons: Set Number of Vertices to 4 and Type to Greater Than. This immediately highlights every illegal n-gon on your model for quick retopology or triangulation.
  • Finding Triangles: Set Number of Vertices to 3 and Type to Equal To (or set vertices to 4 and type to Less Than).