In an earlier video, I spoke of creating a step through frame like this. Suppose we want to make another style of step through frame called a mixte. Instead of a typical top tube, a mixte has an extra set of seat stays that run all the way from the rear dropouts to the head tube.
We'll start by removing the existing top tube. We do that by opening the Tubing dialog box and unchecking the box next to the top tube profile field.
Next, we'll add our second set of seat stays by opening the seat stays dialog box and choosing Symmetric (Double). This will give us a second set of input fields to independently control an additional set of seat stays. We'll change our second set of stays so that instead of attaching to the seat tube, they'll connect to the head tube. Initially, the stays will connect 45mm down from the top of the head tube. We can change this number to 20mm to shift the stays a little further up the head tube.
Next, we can open the Rear dropouts dialog box. We'll notice that we now have the option to independently control the attachment points of the new stays at the rear dropouts. We'll change the S2x value to 20mm and the S2y value to 11mm.