General

The Boolean generator essentially performs the Boolean functions Union, Subtract and Intersect (= intersection).

Shapes created from simple basic objects using a Boolean generator.

In contrast to the old (before Cinema 4D R2025.1) Boolean object, which could only Boolean 2 objects at a time, it is now possible to subordinate any number of objects to a single Boolean generator, each of which can also have its own Boolean functions defined by a Boolean tag.

The first object under the Boolean generator is always the initial object (the cube in the following illustration), from which one object is processed after the other:

It is always processed from top to bottom.

In the Boolean generator itself, you define the basic Boolean function, which initially applies to all sub-objects of the first hierarchy level.

Take a look at the illustration above. On the left you can see the initial situation. In the middle, the Boolean generator (Subtract function) first works by subtracting the Sphere from the Cube. The Cylinder is then subtracted from the resulting shape on the right, where it is then activated

Now it will of course happen that you don't just want to subtract with the Boolean functions, but want to use one of the other functions. For this there are Boolean Tags (Object Manager menu: Tags/Modeling Tags/Boolean), which provide any Boolean function on an object basis:

Boolean tags change the Boolean function on an object basis.

In the above illustration, Subtract always acts as the basic Boolean function; in addition, assigned Boolean tags act as follows:

Left: The sphere has a Boolean tag of the Unite type, so these are additively combined with the original object cube and the cylinder is subtracted from it.
Center: The sphere is subtracted from the original object cube and the cylinder carrying the Boolean tag of type Unite is united with the result.
Right: The sphere is subtracted from the original object cube, the result is used to form the intersection with the Boolean tag of the type cutting supporting cylinder.

Cutting planes

Flat objects such as a plane or disk can be used as a cutting plane. The surface normals of the cutting plane are evaluated here: the part of the original object that is on the side of the surface normal is retained, the other part is cut away.

Ensure that the flat cutting object in the projected normal direction is large enough to completely cover the object to be cut. Otherwise artifacts will occur. If problems occur in connection with sectional planes, try giving the plane a volume, e.g., by subordinating it to a Thicken object.

Interactive operation

The function mode can be changed by double-clicking on the icon in the Object Manager: the available modes are switched through one after the other and the icon is changed accordingly. Incidentally, this also works with the Boolean Tag.

Other interesting facts

Sometimes problems can occur with open volumes when booling. If strange effects occur, try to close the object (in the simplest case, for example, with Close Polygon Hole).
The Boolean generator uses the polygon normals to determine where inside and outside are. So make sure that the normals are in order, e.g., pointing outwards, not suddenly rotated by 180° etc. Otherwise, undesirable effects may occur.
In general, it can help to subdivide the objects involved in the Boolean process more strongly in order to reduce artifacts. As a rule of thumb, the mesh density of the objects involved in the Boolean operation should be of similar dimensions. For example, try cutting 1000 cylinders out of a cube with 6 polygons. This is almost an impossibility, as it results in very long calculation times. However, if you subdivide the cube sufficiently, this is no problem.
The resulting geometry is not triangulated, but retains the mesh structure of the original objects. There are exceptions at the cutting edge, as N-gons are produced here, for example.
Existing Selection tags are processed sensibly and combined if necessary: if objects involved in the Boolean process each have 1 Selection tag with an identical name, these are combined into a single one (if there are several per object, only the first pairs are combined and the others are left separate).