A Relative to Model View is an orthographic (front, right, left, top, bottom, and back) view defined by two orthogonal faces or planes in the model and the specification of their respective orientations. You can use this view type to set the first orthographic view in a drawing to a view different than the default.
You can then create additional orthographic views with the Projected View tool.
For standard parts and assemblies, the entire part or assembly is shown in the resulting relative view. For multibody parts, (such as weldments), only the selected body is used.