What gets added to an assembly when parts are combined?

When parts are combined in an assembly within CAD software, a mate is added to define how those parts interact with each other. Mates establish the relative positions and orientations of components, allowing them to move in relation to one another if needed or to remain fixed together in a specific configuration. This is fundamental because it establishes the assembly constraints necessary for proper functioning and interaction of the components.

Mates can be defined through various types of constraints such as coincident, parallel, perpendicular, and more, which ultimately guide how the parts fit together. These constraints facilitate the assembly process and ensure that parts behave appropriately during simulations or when the assembly is being manipulated for design considerations.

The other choices do not directly relate to the action occurring when parts are combined in an assembly. While materials can be applied to parts, models refer to the digital representations of the parts themselves, and features relate to specific characteristics or operations executed on the components. None of these aspects establish the fundamental connections between parts in the way that mates do.