Which line is used when space is limited and an object must be viewed separately from the main object?

The appropriate line to use when space is limited and an object must be viewed separately from the main object is the break line. Break lines are specifically designed to indicate that an object or a section of an object has been "broken" to fit a drawing or to show additional detail without expanding the overall size of the drawing. This helps to keep the drawing neat and easy to read while still providing a clear representation of the design.

In scenarios where space constraints necessitate showing parts of an object or additional details, the break line is ideal because it allows for a segment to be left out or simplified while maintaining the overall context of the design. This technique is commonly used in technical drawings to illustrate components such as pipes or beams, where only a portion of the item is relevant to the viewer.

The other line types serve different purposes: movement lines indicate motion, dashed lines often represent hidden features, and solid lines typically show the visible edges of objects. However, none of these options are specifically intended for indicating a break in the object for better visibility when space is limited.