NeuTu uses a “bookmarking” system to mark bodies or areas of interest. Bookmarks are point annotations that can be imported as a list or added by the user. Bookmarks appear as red open circles in the 2D window. A bookmark can be added by mouse click in the 2D view (user bookmark) or loaded from a bookmark file (assigned bookmark). A user bookmark has a letter U showing on its glyph side, while an assigned bookmark is only displayed as a circle.
To place a user bookmark, the user must hit the “G” key to enter the bookmarking mode. Click on mouse to add bookmark and double-click to annotate with free form text. User bookmarks can be selected and deleted as well ('Delete' or 'X'). We can double click on a bookmark to change its annotation content. Bookmarks are classified into three types: Merge, Split and Other. Merge and Split bookmarks can be used to mark falsely merged bodies and falsely split bodies. Other-type bookmarks can be used to label specific bodies for proofreading assignments.
Users can import an “assigned” list of bookmarks using the Bookmark button in the top left menu bar. NeuTu also displays bookmarks and sorts them in ascending order by Z and shows the body ID and comments associated with each bookmark.