What is a boolean modifier and how do I use it?
How Boolean Works
The boolean modifier uses a second object, often called the cutter, to change the first object's shape. Difference removes the cutter's volume from the target, which is useful for holes and slots. Union merges the two shapes into one, and Intersect keeps only the area where they overlap.
Keeping the cutter as a separate object lets you move or adjust it without re-doing the whole model. Many artists hide the cutter from view once the boolean is set so they can see the result clearly.
- Difference: cut holes and slots
- Union: combine two shapes
- Intersect: keep only the overlap
- Hide the cutter after setting it up
Getting Clean Results
Boolean results depend on clean geometry. Non-manifold edges, overlapping faces, or loose vertices can cause errors or holes in the result. Run a quick mesh cleanup before combining objects.
The Exact solver is more accurate but can be slower on complex models, while Fast works quicker with simpler shapes. Choose the solver that fits the detail you need, and apply the modifier once you are happy with it.
Booleans also work well for repeated shapes like grids of holes. Duplicate the cutter, arrange the copies, and combine them with an Array modifier when it fits the design. This keeps the setup flexible and easy to adjust later in the project.
Common mistakes
- Using a cutter that is not closed, which leaves gaps in the result.
- Stacking many booleans on a heavy model and slowing down the viewport.
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