Which assembly feature allows you to prevent linear movement between parts?

The correct choice is the Fixed feature, which is used to prevent linear movement between parts in an assembly. When a part is fixed, it is effectively anchored in place, which means it cannot be translated or rotated within the assembly. This characteristic is essential in scenarios where you want to maintain the position of specific components while allowing others to move relative to them.

The Fixed feature is particularly useful in assemblies that require certain parts to remain stationary while others are being manipulated or assembled. It provides a level of stability and control in complex designs, ensuring that the integrity of the assembly is maintained.

In contrast, while a Rigid Group can hold multiple parts together to behave as a single unit, it does not prevent linear movement if the entire group is not fixed. Joints allow for controlled movement and are typically used to define the allowable motion between parts rather than prevent it. The Pin feature also facilitates rotational movement while constraining linear motion only in one direction, but it does not provide complete immobilization as the Fixed feature does. Therefore, for maintaining a part's position in its assembly without any degree of movement, the Fixed feature is the appropriate choice.