I was recently asked about instance parameter grips for a Revit family that was placed in a Revit project file. The family had an instance parameter in it for a dimension and the user was expecting to see grip arrows so that they could manually adjust the size by dragging the grips. The arrow grips did not exist and the user was curious why that was the case.
The answer to the user’s question is actually very simple. When creating a dimension that will be referencing an instance parameter, it is important to dimension between two Reference Planes for the grip arrows to appear.