active component A selected component currently being edited. This component is underlined in the specification tree.
active object An object currently being edited.
assembly An entity composed of various components which have been positioned relative to each other.


bill of material A list of data about the properties of the components contained in the active component.


CATShape A document that contains the graphic representation definition of a part (Physical shape of the part). The user can define one or more CATShape (graphic representation) for a part. The primary graphic representation resides in the CATPart document, one or more secondary representations can be defined in CATShape documents. CATShape files can be exported to STEP or 3D IGES.
child component One or more components originating from a single component. Compare parent component.
component A reference integrated in an assembly. A component possesses characteristics related to how it is integrated in an assembly (for example, its relative location in an assembly).
constraint A geometrical or dimensional relation between several geometric elements of different components. It may be used to define the positioning of components.
A hierarchical design of an assembly in a specific context (for example: engineering or manufacturing).


geometric element The geometric elements which can be constrained in the Assembly workbench are: point, line, plane (or plane surface from a model), sphere, cone, cylinder.


leaf component The last component at the end of each branch of the specification tree.


manipulation A freehand translation or rotation of a component with the mouse.
model A CATIA Version 4 model.


parent component A component that is hierarchically just above one or more components. Compare child component
part Within the Assembly workbench, it is either a part of the Part Design workbench, or a 3D entity whose geometry is contained in a model.
primary child
One or more components originating from the first level under the active component.
product A 3D entity which contains several components.


reference A product or part with its own characteristics. Compare component.
representation See context specific representation.


Sag Used in the Part to Part Clash and the Clash commands. Corresponds to the fixed sag value for calculating tessellation on objects (3D fixed accuracy) set in the Performances tab of Tools > Options > General > Display. By default, this value is set to 0.2 mm. 
search order A hierarchical set of paths used when searching for the files included in the assembly. The search begins with the first path, and stops when the file is found.
subassembly An assembly contained within another assembly.


Tessellation A tessellation (or polygon or mesh) consists of a set of polygonal faces which represent the surface of a 3D model. A triangulation is computed to describe the neighborhood relation of all points.


update In the Assembly workbench, updates the position of the constrained components so as to satisfy the constraint requirements.