When adding extra tubes in BikeCAD version 18, we now have the option to attach the new tube at only one end. To do this, select None for the first tube. Dimension DA becomes the length of the new tube and we get a new dimension ϑ which defines the angle at which the new tube branches off its connecting tube. In this case, we can use our extra tube to extend our top tube beyond the head tube.
This opens up other possibilities such as designing our own custom rack mounted to the seat stays. Another new feature of BikeCAD version 18 is the option to attach extra tubes to other extra tubes. We'll use that feature in this example to complete our rack.