**Associativity**: an associated link between two different components of a CAD system. When a change is made to a feature, a related feature is also updated. For example, a 3D model can be associated with drawings so that a change in the model is reflected in the drawings. Bi-directional associativity is a function where an update can occur both way. A change in either the model or drawing will be associated to the corresponding component. For Ex. from function A to function B as well as function B to function A.

**Axis**: A spatial direction along which the path of motion. There are three primary axes, X, Y and Z. Each primary axis has a relative axis along that axis; A, B and C.

**A-Axis**: The axis of motion that revolves along the X-Axis.

**B-Axis**: The axis of motion that revolves along the Y-Axis.

**Boolean**– a 3d modeling function used to modify or create a solid body by combining, subtracting, or intersecting more than one body.

**Boundary**: a geometric parameter of constraint used to confine or exclude a toolpath.**Boundary Representation ( B-Rep)** : a method used in solid modeling to define geometry that’s represented by edges, faces, and vertices.

**CAD**: Computer Aided Design; The use of computers to assist in the design process.

**CAM**: Computer Aided Manufacturing; The use of computers to assist in manufacturing.

**Cartesian Coordinates**: A three dimensional system used to represent a position, location, or direction of motionin space.

**C-Axis**: The axis of motion that revolves along the Z-Axis.

**Circular Interpolation**– A toolpath that moves along a circular arc. Circular interpolation is defined by: an endpoint

- an endpoint
- a feed rate
- a center point or arc center
- a radius
- a direction of movement

**Cloud of points**: a set of data points generated from a 3D scanner or digitizer that is used to define xyz coordinates. The data is used to represent or map out a solid body or surface.

**Constraints**: Spacial parameters or boundries that are used to define relationships within within geometry. Constraints may be used to associate parametric or variational geometry within a CAD system.

**Constructive Solids Geometry (CSG)**: a 3d modeling method using primitives to build more complex models and Boolean operations of add, subtract, and intersection.

**Cutter Diameter Compensatio**n (CDC) : A programming method used to alter a toolpath to compensate tool diameter wear.

**Cutter Offset**: The axial distance from the cutting tool center to the cutting tool diameter (Tool Radius).

** Cycle**: The sequence of operations and repeated processes that a CNC executes within a program. also see Cycle Time.

**DWG**: A 2d CAD drawing file format commonly used in Autocad.

**DXF** (Drawing Exchange Format): a common file format for 2d CAD drawings and geometry used to transfer CAD data from one CAD system to another.

**Interpolation**: A CNC function where generated data points control movement to a given coordinate position.

**Linear Interpolation**: A CNC function where generated data points control movement to a given coordinate position to allow simultaneous motion to one or more axes in a linear path.

**Lofted surface**: A surface created by fitting a shape to a series of 2D cross-sections.

**Loop**: A programming method used for continuous repetitive operations where the operator will input the needed number of repetitive tasks.