Is it possible to make the plane markup type persistent, or to change the default type? I usually use the 3-point placement method, but am needing to change this for each plane, even when in persistent placement mode.
You can register a default vtkMRMLMarkupsPlaneNode in the scene and set the plane type to anything that you prefer. You can do this in the application startup script.
If you find that you or users wants to set this often, then you could add an “Advanced” section in “Plane settings” with a “Save to defaults” and “Reset to defaults” buttons.