Boolean

The boolean modifier implements high quality 3d boolean algorithm. This modifier provides standard boolean operations along with few specific ones.

Boolean modifier works with two operands: A and B.

For OR, AND and SUB opeartions Each object should be closed - without holes and self intersections. Small holes are allowed but may cause wrong results.
If you want to process mutiple objects, make chain of boolean modifiers or make group for A or B opearnd. Whole group will work as single operand. There is one limitation, objects inside of such group shouldn't intersect each other. For example, see image below.
It is possible to change order of objects by drag&drop or selecting different mode. For instance b SUB a instead of a SUB b.

Properties of Boolean modifier.

Mode

Boolean operation:

MERGE	Combine two source objects. This is not a boolean operation, just combining of geometry without any logic.
a OR b	Make UNION of two objects.
a AND b	Make INTERSECTION of two objects.
a SUB b	Subtract b from object a.
b SUB a	Subtract a from object b.
a CUT b	Subtract b from object a. This is not a classic 3d boolean operation, it leaves only parts of first object which are inside of second one. Produced surface is not closed and first object may be not closed too. See image below for an example.
b CUT a	Subtract a from object b. See previous mode.
~(a CUT b)	Opposite to a CUT B. Opposite means that parts which are outside of second objects will be in produced object.

Preserve Normals

Keep normals of source objects.

Optimize Result

If checked, result will be optimized by removing extra points, joining edges, removing small holes. See example below. This option applied optimizer modifier internally with default options, if you need more control, disable this option and apply Optimizer modifier.

Enabled

Enable or disable modifier. When disabled, it works like regular node.

Advanced Properties

Relative Treshold	In case if results are wrong because of mathematical precision, you may play with threshold value.
Flat Surfaces	One of the special cases is flat surfaces which are touching each other. Settings below, may help to activate special algorithm for processing such surfaces.
Max Angle	Angle between surfaces. Angle is measured degrees.
Max Distance	Distance between surfaces.

Reset	Restore all values to defaults.
Force Output in Double Precision	If checked, vertices of produced geometry will be in double precision.

Example 1

Source object A and group of objects (as B operand):

Example 2

Optimize result Off.	Optimize result On.

Example 3

CUT operation. Compare with SUB on previous image.