public static void CreateDimensionElement(
Document doc,
Autodesk.Revit.ApplicationServices.Application app,
Autodesk.Revit.DB.View view,
XYZ p1,
Reference r1,
XYZ p2,
Reference r2)
{
Autodesk.Revit.Creation.Application creApp = app.Create;
Autodesk.Revit.Creation.Document creDoc = doc.Create;
ReferenceArray refArr = new ReferenceArray();
refArr.Append(r1);
refArr.Append(r2);
Line line = Line.CreateBound(p1, p2);
Transaction t = new Transaction(doc, "Dimension Two Walls");
t.Start();
Dimension dim = creDoc.NewDimension(doc.ActiveView, line, refArr);
t.Commit();
}