Auto regions always dynamically update to assembly changes and the shape of the route can vary from the original auto route solution. They do not involve dimensions until you convert them to parametric regions.
For parametric regions, there are three typical types of dimensions pertaining to the route sketch:
As in Autodesk Inventor, dimensions on the route sketch can be categorized into two types:
Used to drive the route geometry. For instance, sketched route segments are manually created using a specified normal sketched dimension.
Enclosed in parentheses as displayed in the graphics window, and allows route geometry to respond dynamically to associated changes. It typically occurs on the route sketch that relates to the assembly geometry or when an auto region is converted to a parametric region.
You can switch between the driven dimension and the normal sketched dimension using the Driven Dimension command. Once a driven dimension is switched to a normal sketched dimension, you can edit the value. If converting the driven dimension to a driving dimension over-constrains the geometry, the conversion is not allowed.
Driven Dimension
In the route environment, normal sketched dimensions can be manually set using the General Dimension or edits in place. You can place dimensions based on geometry outside of the active route. First include it in the route sketch using the Include Geometry command.
General Dimension