The relative view feature can be found when working on a drawing and lets you insert an orthographic view of an assembly, part, or individual bodies. This view can be in a custom orientation taken from select faces and planes. This feature can be found by going to Insert > Drawing View > Relative To Model, or by right clicking on an existing view, from which you want to make the view of, and selecting Drawing Views > Relative View.
Examples of where this feature is useful is when you have a part with an angled face and want to have a view perpendicular or normal to it, that isn’t achievable using the standard views. Another is when using a weldment part or multibody part and you want to isolate one or more bodies, with the option of re-orientating them at the same time.
The short video below walks through how to insert a relative view using these two example:
If any changes are made to the model the relative view will update to always use the same faces chosen to determine the orientation. It can also be useful to create views based from a re-orientated view, such as projected, section, etc.
This is a useful feature to help improve the clarity of drawings created in SolidWorks.