To display midpoints, choose “Midpoint-Trees” from the View-menu. You get the best display option, if you select “none” from the list menu. Midpoint-Trees are available since Version 4.04.
Every object that is selected in Objects dialog at Object Selection: Radix: Inner will be the root of a Midpoint tree as of Version 4.04
Every object that is selected in Objects dialog at Object Selection: Midpoints: Inner will be considered as possible member of the branches of a Midpoint tree as of Version 4.04
Every aspect that is selected in Objects dialog at Aspects Settings: Radix: Inner will be considered as possible aspect displayed in a Midpoint tree as of Version 4.04
Midpoints will, as of now, be cast for the positions of the inner chart, whatever type of chart is chosen.
Please note, that also aspect-orbs and object-orbs have their own setting for midpoints and make sure you set a value that is not too high, there.
To print Midpoints, make sure that the selection of the Midpoint-view is somewhat resembling the proportion of the chosen page format of your printing dialog. In extreme cases not all of what you can see in the window would be printed, so always first choose page format and then on actual printing have a look at the print-preview first.
Here is how your window should look for landscape view, if the trees grow too high, reduce the aspect-orb with the orb choker (red oval):
Yet, if you love high growing trees, choose portrait mode and adjust the window like so:
Playing with the settings and with your window setup will soon show you the best way to display and print your midpoint-trees.