A computerized online engineering tool system for specifying the various components of a holdown system that assemble a run comprising a tie rod extending inside a frame wall structure from the foundation up through the walls to the top floor, and bearing members and tension devices securing the tie rod to the wall. The system comprises a server including a database of drawing elements and hardware parts; a program residing in the server including the steps of allowing a user to login into the server; providing the user a settings page to allow the user to select options for the run; providing the user a data input and calculated data page for inputting uplift, tension or overturning load at each framing level and showing calculated rod elongation at a framing level and rod size sufficient to handle the uplift load; and providing the user a print and download page for allowing the user to download a shop or installation drawing of the run generated using the drawing elements and hardware component parts from the database.