BikeCAD has always offered several ways to control front end geometry.
You can choose to directly input effective top tube length and top tube angle. When this option is chosen, these are the values that remain fixed as other dimensions such as head angle and stem length are adjusted.
You can choose to directly input front center and head tube length. When this option is chosen, these are the values that remain fixed as other dimensions such as head angle and stem length are adjusted.
We will observe similarly predictable behaviour when controlling by Handlebar from BB in X and Y coordinates as well as when controlling by stack and reach.
In BikeCAD version 16, we have two new methods for controlling front end geometry. First is the distance from the saddle to the handlebars paired with the distance from the BB to the handlebars. The second is the distance from the BB to the hands paired with the angle formed by this line running from the BB to the hands. If this final option is to be used on a road bike, the fitter should standardize on which hand position they will be measuring to. The tops, hoods and drops are all viable choices.