I have made an extruded part (not yet converted to sheet metal), I used a sketch and then added a linear feature pattern to make the 3 'valleys' from the orginal feature.  The only problem with it is if i change dimensions to the original feature I have to change the pattern dimension.  If I use a sketch pattern i have to dimension each child all over again..cumbersome.  I need the child features to meet exactly at a certain location in order for it to merge cleanly.  Any good ways to do this?