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Since Blender 4.5’s recent release included major improvements to the Boolean modifier,

I figured it’s time to do a deep dive into how to use the Boolean modifier in Blender.

If you plan on using these modifiers a lot, you’ll actually want to use the Bool Tool,

which is a free tool that’s included in Blender and we’ll get to that at the end.

My name is Brandon. I’m a real human being and I strive to make

thorough Blender tutorials without the fluff. So let’s get started.

The main use of the Boolean function is to use one

object to cut shapes into or out of another object.

Here’s an example of what that can look like. We have a cylinder cutting into a

UV sphere. We can move, scale, or rotate the sphere and it doesn’t actually change

the mesh of the sphere, yet. Meaning it’s non-destructive.

So how do we do this?

Select the object we want to be modified by the Boolean. Or,

most often, this is the object we want to cut into.

Go to the modifier properties tab and choose “Add Modifier.”

Search for “Boolean.”

Or you can find the boolean modifier under the Generate category.

Here’s our modifier, we will cover all the settings as they come up.

The first thing we want to decide is what object or objects should

affect the shape of the sphere. In this case, we are using the cylinder which is

a single object. So the “Operand Type” is the default of “object.”

The other option here is “Collection.” So if we wanted multiple objects to be used

to cut the sphere, we could add them to a collection and use the Collection as a

cutter. This would allow us to use one modifier for multiple cutting objects,

instead of having to add a boolean modifier for every single object we want to use as a cutter.

With Object as the type, we can choose from any object in our scene. Click this

drop down and you’ll get a list of all the objects to choose from. In a real scene,

you might have hundreds or more of these, so the easiest way is

probably to click the eye dropper tool on the right and then click on the object we

want to use as the cutter. I’ll click this cylinder and it’s now the cutting object.

Now as I move this cylinder around, it’s actually cutting into the sphere non-destructively. But,

that’s hard to see because the cylinder is fully visible.

We could select the cylinder and press “H” to hide it, and we can see it’s cutting a

cylinder-shpaed hole into the sphere, but now we can’t select the cylinder or move it around.

So here’s a better option. Press Alt+H to unhide the cylinder. With the cylinder selected,

go to its object properties tab. Scroll down to “Viewport Display” and where it

says “Display As” change this to “Wire.” Bounds will also work but I prefer wire.

Now we can see what the cylinder is doing to the sphere, but we can still select and manipulate it.

We’ve got more important things to cover, but if you’re still here,

please hit that like button!. It means the world to me. Thank you so much!

Let’s click back on the sphere to see what’s happening.

The Boolean modifier has three modes of operation. The default is “Difference.” And

this is the one we want to use to cut shapes out of an object. It’s called difference because it’s

subtracting the shape of the cylinder from the sphere and if you remember basic math,

when you subtract something the result is the difference.

If we changed this operation to “Intersect” it will remove all parts of the sphere except for

those that intersect with the cylinder. So this is another use of the boolean modifier.

And if we choose “Union” it will add the two shapes together.

Let’s click back to difference and then press “tab” to enter edit mode.

Despite the look of the object being changed, the actual mesh of the sphere has not been

altered. That’s because the boolean modifier is non-destructive. It’s only when we apply

the modifier, if we choose to do so, that it will permanently affect the shape of the mesh.

Until then we can move, rotate, and scale the cylinder to change

the shape of our boolean and nothing is permanently damaged.

We could also make as many changes as we want to the cylinder’s geometry and

that will be reflected in the cut of the boolean.

That’s the bulk of the boolean modifier, but let’s talk about these solver options.

I rarely mess with these, but there are now three “solvers” which are different

ways that Blender calculates the Boolean modifier. The manifold solver was recently

added in Blender 4.5. Basically “Float” is a simple calculation that will work

faster and the “Exact” solver is more accurate but can be a bigger

drain on your system to calculate. It could really slow down your viewport.

The new “Mainfold” is super fast and it’s probably what you want to use now,

but it only works on “Manifold” meshes, which means the meshes are fully enclosed.

There are additional “Solver Options” which are way beyond my comprehension

and I doubt you’ll ever need to mess with these.

The last thing we’ll do is to apply the modifier. Remember you don’t always have

to apply modifiers. You can render without the modifiers being applied,

but if you ever need to export this 3D object for use outside of Blender,

you’ll definitely need to apply the modifier, which makes it permanent.

To apply a modifier, we click this arrow and choose “Apply.” Now, we could delete

the cylinder because it’s no longer needed as a cutter. If we click into edit mode on the sphere,

we see the mesh has been altered to reflect the sphere’s new shape.

One of the reasons why people don’t like to use Booleans is that they can create pretty

sloppy geometry. You can see we have a lot of nGons here. If that’s a problem for you,

and what you’re doing, then Booleans might not be for you. But if it’s not,

it’s a super cool tool for hard surface modeling in Blender.

I mentioned the Bool Tool at the beginning. The Bool Tool is a free

extension available in Blender, we just have to activate it. Among other things,

it adds some quick shortcuts to speed up the process of using booleans.

To activate the Bool Tool extension, go to Edit… Preferences. Then go to “Get Extensions.”

If we search for “Boo,” we can install the Bool Tool. Try saying that three times fast.

Now, let’s start over from scratch. Let’s say we want this cylinder to cut a hold into this cube.

We select the object we want to be the cutter first. Then we hold shift and select the object

we want to be cut. So the object that the modifier is going to go onto is selected last.

To activate the bool tool using the “Difference” method,

we press Control and then minus on our num pad.

That shortcut added the boolean modifier to the cube, selected the cylinder as the cutter,

and set the display mode to “Bounds” all at once. As far as I know,

the tool can only used for cutting one object at a time.

There are also shortcuts to use the “Intersect” and “Union” options.

I’ll put a complete reference guide for the boolean modifier and the Bool Tool on my

website at Brandon3D.com. Please hit that like button, become a subscriber and stay creative!