Modeling · Beginner

Boolean

Combining or cutting two shapes with union, difference or intersect

Also called Boolean operation

What is a boolean in 3D modeling?

A boolean is an operation that combines two shapes into one: union merges them, difference cuts one out of the other, and intersect keeps only the part where they overlap. It is a fast way to drill holes, carve slots and join parts, though it often leaves messy faces to clean up.

Think of it like this

It is like a cookie cutter: press one shape into the dough to cut out a hole, or keep only the piece inside the cutter.

Where it fits in a 3D project

  1. Create
  2. Surface
  3. Rig
  4. Animate
  5. Render
  6. Export

Create: Building the shape: modeling, sculpting, scanning or generating it.

How a boolean works

  1. 01Place a cutter object where it overlaps the main model.
  2. 02Choose union, difference or intersect.
  3. 03The software works out where the two surfaces cross and builds new faces there.
  4. 04Clean up long, thin triangles and n-gons left along the cut.

Where a boolean is used

  • Cutting holes, slots and vents in hard-surface models
  • Joining parts into one solid for 3D printing
  • Quick blocking of mechanical and architectural shapes

Beginner tip

Booleans work best on closed, watertight meshes with correct normals. If a cut fails or leaves holes, check both objects for gaps, flipped faces and unapplied scale first.

Terms related to a boolean

Boolean FAQ

What is a boolean difference?
Difference subtracts one shape from another, like drilling a hole in the cutter’s shape. It is the most used boolean, for holes, sockets, slots and engraved details.
Why do booleans create bad topology?
The operation only cares about where surfaces cross, so it slices faces wherever they meet. That leaves long, thin triangles and n-gons, which can shade badly when smoothed. Cleaning up the cut or adding a bevel usually fixes it.
How do I use booleans in Blender?
Select the main object, add a Boolean modifier, choose the operation and pick the cutter object. Hide the cutter to see the result. The modifier stays live until you apply it, so you can still move the cutter.

Updated October 29, 2026 · Browse all 3D terms