1. A method of assisting a user in selecting a join for a structure represented in a computer model, the method comprising: receiving, via a join-recommending system, a join request for joining two structures with a weld; receiving, via the join-recommending system, input joining data, the input joining data including characteristics of the two structures, the characteristics including material type, geometry, and weld location; generating, within the join-recommending system and in response to said receiving the join request, a recommended joining data as a function of the input joining data, the recommended joining data including at least tow different weld types, the generating step including calculating, based on the input joining data, a joint strength and manufacturing cost for each of the at least two weld types; presenting the recommended joining data to the user via a join-recommendation user interface, the interface including a panel for displaying the at least two different weld types and a panel for displaying the calculated joint strength and manufacturing cost for each of the at least two different weld types; receiving via the join-recommendation user interface a user selection of the recommended joining data so as to create selected joining data; and automatedly associating the selected joining data with the computer model.