NURBS Booleans

Notes:

  • Select either the first object or all the objects before starting the command.

  • Boolean commands can also be used with surfaces and open polysurfaces
    . The result depends on the direction
    of the normals of the object. Use the Dir
    command to see the direction. If the results are the opposite of what you want, reverse the direction of the surface with the Dir
    or Flip
    commands and try again.

  • Try the Join
    command first on surfaces.

  • For mesh objects see the Mesh Boolean
    commands.

BooleanDifference

Cuts away the shared areas of selected polysurfaces
or surfaces with another set of polysurfaces or surfaces.

Steps:

  1. Select

    the first set of objects, and press Enter

    .

  2. Select the second set of objects, and press Enter

Option

DeleteInput

Rhinoceros BooleanDifference Booleans

Solid Tools > Boolean Difference

Rhinoceros Menu2 Booleans

Solid > Difference

Rhinoceros Gray Book Open Booleans Related topics…

BooleanIntersection

Cuts away the unshared areas of selected polysurfaces
or surfaces.

Steps:

  1. Select

     the first set of objects and press Enter

    .

  2. Select the second set of objects and press Enter

    .

Option

DeleteInput

Rhinoceros BooleanIntersection Booleans

Solid Tools > Boolean Intersection

Rhinoceros Menu2 Booleans

Solid > Intersection

Rhinoceros Gray Book Open Booleans Related topics…

BooleanUnion

Cuts away the shared areas of selected polysurfaces
or surfaces and creates a single polysurface from the unshared areas.

Steps:

  • Select

    the objects and press Enter

  • The objects combine into one polysurface.

Option

DeleteInput

Rhinoceros BooleanUnion Booleans

Solid Tools > Boolean Union

Main2 > Boolean Union

Rhinoceros Menu2 Booleans

Solid > Union

Rhinoceros Gray Book Open Booleans Related topics…

BooleanSplit

Cuts away shared areas of selected polysurfaces
or surfaces and creates separate polysurfaces from the shared and unshared parts.

Steps:

  1. Select

    the first set of objects and press Enter

    .

  2. Select the cutting objects and press Enter

    .

  3. Note: The cutting objects and the objects to split can be the same objects.

Option

DeleteInput

Rhinoceros BooleanSplit Booleans

Solid Tools > Boolean Split

Rhinoceros Menu2 Booleans

Solid > Boolean Split

Rhinoceros Gray Book Open Booleans Related topics…

Boolean2Objects

Enables iterating through Boolean operations (Union, Intersection, Difference A_Minus_B and B_Minus_A, and Inverse) with mouse click.

Steps:

  1. Select

    two objects.

  2. Click the mouse in the viewport until you get the object you want.

Option

DeleteInput

Rhinoceros Boolean2Objects Booleans

Solid Tools > Boolean 2 Objects (Right click)

Rhinoceros Menu2 Booleans

Solid > Boolean Two Objects

Rhinoceros Gray Book Open Booleans Related topics…

Mesh Booleans

The steps are the same as for the NURBS Boolean equivalent.

Note: The result of a command is always a mesh regardless of the input object type.

MeshBooleanDifference

Cuts away the shared areas of selected meshes, polysurfaces
, or surfaces with another set of meshes, polysurfaces, or surfaces.

See: BooleanDifference

Rhinoceros MeshBooleanDifference Booleans

Mesh Booleans > Mesh Boolean Difference

Rhinoceros Menu2 Booleans

Mesh > Mesh Boolean > Difference

Rhinoceros Gray Book Open Booleans Related topics…

MeshBooleanIntersection

Cuts away the unshared areas of selected meshes, polysurfaces
, or surfaces.

See: BooleanIntersection

Rhinoceros MeshBooleanIntersection Booleans

Mesh Booleans > Mesh Boolean Intersection

Rhinoceros Menu2 Booleans

Mesh > Mesh Boolean > Intersection

Rhinoceros Gray Book Open Booleans Related topics…

MeshBooleanUnion

Cuts away the shared areas of selected meshes, polysurfaces
, or surfaces and creates a single mesh from the unshared areas.

See: BooleanUnion

Rhinoceros MeshBooleanUnion Booleans

Mesh > Mesh Boolean Union

Mesh Booleans > Mesh Boolean Union

Rhinoceros Menu2 Booleans

Mesh > Mesh Boolean > Union

Rhinoceros Gray Book Open Booleans Related topics…

MeshBooleanSplit

Cuts away shared areas of selected meshes, polysurfaces
, or surfaces and creates separate meshes from the shared and unshared parts.

See: BooleanSplit

Rhinoceros MeshBooleanSplit Booleans

Mesh Booleans > Mesh Boolean Split

Rhinoceros Menu2 Booleans

Mesh > Mesh Boolean > Boolean Split

Rhinoceros Gray Book Open Booleans Related topics…

Troubleshoot Boolean Operations

Rhinoceros Gray Book Open Booleans Related topics…

Boolean operations can fail for a number of reasons:

  • Normals may not point the way you expect.

  • Control points
    tend to stack up at the intersection of the two objects.

  • Objects may have overlapping surface areas.

Surface Normals

The Boolean operations use the surface normal to determine which pars to keep and which to throw away. When you attempt a Boolean Difference and you get a Union instead, or vice versa, this is because the objects have normals that are the opposite of what you expect.

Boolean operations tend not to work well if the objects have overlapping surface areas, or only touch each other at a particular location or along edges. For success using the Boolean operations, the objects should push all the way through one another and not be tangent.

Coincident Control Points

Coincident control points occur when the control points at the edge of a surface are at an identical location. This occurs in Rhino naturally at the tip of a cone or the pole of a sphere or a three-sided plane. You can also move control points to the same location. This point is also called a singularity.

When a singularity point occurs at the intersection of two objects you want to Boolean, the operation can fail.

Rhinoceros when booleans fail 002 Booleans

Overlapping Surface Area

Overlapping surface areas occur when two surfaces share the same area. In this example, the two boxes are just touching along one side. The objects will Union
, but Difference
, and Intersection
will not work.

Rhinoceros when booleans fail 003 Booleans

What To Do

If your objects won’t Boolean, you can use other techniques to get the results you want.

In this example, the apex of the cone is exactly at the corner of the box. This is one of the situations that can cause the Boolean operations to fail.

Instead of using Boolean operations in this case, use the Explode
command to separate polysurfaces into single surfaces if necessary. Use the Intersect
command to create curves that represent the intersection of the two surfaces. To create the parts, use these curves to Trim
and/or Split
and then Join
them back together.

 

Booleans