If you intend to build a bike with S & S couplings, you may like to visualize how that bike might pack into a box when broken down. In BikeCAD version 9.0 you can click on the box icon 
and click Add to display a box on the screen. The default box will be 26" by 26". We can see these dimensions on the screen if we click on the width (W) and height (H) dimensions in the Components >> Boxes tab in the Dimensions dialog box.
In the boxes dialog box we can control the width and height of the box as well as it's angle and position on the screen. However, an alternative to moving the box around by editing text fields, is to click the Move button and simply drag the box around on the screen. The angle of the box can be changed by holding down the ALT key and dragging the mouse up or down.
In this example, we might drag this 26" square box to confirm that the back end of the bike can fit into the box with the cranks still attached. Then we can add a second box and confirm that the front end of the bike can fit into the box with the stem and fork still attached. If we turn on the display of S & S couplings we can see that it would be suitable to locate the couplings on the top tube and down tube anywhere inside the region where both boxes intersect.