The Boolean Modifier performs operations on meshes that are otherwise too complex to achieve with as few steps by editing meshes manually. The Boolean Modifier uses one of three Boolean operations that can be used to create a single mesh out of two mesh objects:
To use the Boolean Modifier select the desired mesh Object then add a Boolean Modifier. When you add the Boolean Modifier for an object, Blender will need a second object to be the target of the operation. You can use open or closed meshes, as long as they have available face normals for the calculations to take effect. You can add one or more modifiers of this type for an Object but you can only apply one operation for the Boolean Modifier at a time.
If you have marked your Objects to show the Edges (in, enable Wire), you will see the Edge creation process while you are moving your Objects. Depending on your mesh topology, you can also enable X-Ray and Transparency and see the topology being created in real time.
Boolean operates best on water-tight meshes, where inside/outside is clearly defined.
The following characteristics are known to give bad output.
- Open volumes.
- Overlapping geometry.
- Zero-area faces.
While they may not fail in all situations, they aren't guaranteed to work properly.