Object Tree
All segmentation operations result in virtual reality objects which are arranged as an object tree in the View tab as illustrated in the example below.
Entries with SR represent surface renderings, VR volume renderings, the Surface Light is the optional lightning source for SR objects, the Markers are synthetic objects usable for indicating points of interest, the Planes are sets of image slices, and Note is a text shown in a corner of the 3D scene. If an object is not needed any more, it can be removed from the tree by the Remove button.
The 
buttons are used to create ghost objects, which are empty SR or VR objects with defined visualization attributes. These attributes will be used for rendering the objects resulting from the next segmentation. The advantage of using ghost objects is avoiding lengthy rendering operations with inadequate default settings.
To delete a 3D object select the corresponding object in the tree and then activate Remove. The 
button collapses the tree, whereas 
expands it fully.
Object Properties
Every object type has a set of visualization attributes which are shown in the lower panel as soon as it is selected in the tree. Its tab name corresponds to the object type, Surface, Volume, Planes etc. The visualization attributes are described in the next sections. Note that if a sub-tree or several objects in the tree are selected, the common properties may be manipulated for all contained objects at once.