Boolean?

What are Booleans?
In Maya a Boolean is an operation that is performed one two objects to create a single compound object. You can apply three different types of Boolean operations: Union, Difference and Intersection.

How do Booleans work?
Applying a Boolean is quite simple. You select both objects and go to Mesh->Booleans and select which Boolean operation you would like to perform. If you are unsure which operation is the right one, do not worry – You can always change the type of Boolean in the channel box later on (Assuming you have history turned on).
When applying a Boolean Maya takes into account the volume of the two selected objects and the space both objects might share. The easiest way to understand Booleans is to think of the operation as a Math Formula. The first selected object will be A, the second object will be B and the compound object after the operation will be C. So the formula goes like this: Object A (BOOLEAN OPERATION) Object B = Object C. This might seem confusing at first, but it will make a lot more sense once you have read the next section.

What are the different Boolean operations?

Union: A + B = C. Union will combine the volume of both objects into a single object. It almost works like
Mesh->Combine with the difference that Union will take out the shared space between object A and B.

Difference: A – B = C. Difference will subtract the volume of object B from object A. Note that Difference only works if both object share space in between them. You could also say that you are using object B to drill a hole into object A. The shared space will be the drilled hole and object B will disappear completely afterwards. Keep in mind that selection order is of vital importance when using the Difference operation: First selected object is A, second selected object is B. If you are unsure which object you selected first take a look at the colors of your edges. Object A should be highlighted white, object B should appear green (assuming that you haven’t changed you Color output).

Intersection: A % B = C. Intersection deletes both objects and leaves only their shared space. As the name of the operation implies object A and object B need to actually share space in between them – otherwise you will be left with no geometry after the operation has been performed.