Perform boolean operations on surfaces

Boolean operations are actions that trim surfaces to create the appearance of a union, intersection, or subtraction between two objects.

To perform a boolean operation on a surface

1. Choose an action from the Edit NURBS > Booleans submenu.
   • Union trims the surfaces so they appear to be merged.
   • Difference trims the surfaces so that the volume of the second surface appears to be subtracted from the first.
   • Intersection trims the surfaces so that only their shared volume remains.
2. Click the first surface and press . Then click the second surface.

   The order in which you click the surfaces only matters for the Difference tool. Maya subtracts the second surface you click from the first.

   

   Maya groups the combined surfaces.

You can make the following adjustments after creating the Boolean shape:

• To change the Boolean operation, such as changing Difference boolean to an Intersection boolean, select the boolean node in the Channel Box and change the Operation option.
• You can select the node of one of the original objects in the outliner or hypergraph.
  
  Note

  The only way to retrieve the original objects after a Boolean operation is to use Undo.

Troubleshooting boolean operations

If you get a “not a valid NURBS shell” error it means the boolean tool cannot create meaningful geometry from the surfaces you clicked.

For example, in the following illustration, the horizontal cylinder does not enclose a space that can be combined with the vertical cylinder. If you move the horizontal cylinder up, the boolean actions will work.

Related topics

• Trim or untrim a NURBS surface
• Edit NURBS > Booleans > Union Tool, Difference Tool, Intersection Tool

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