If the P3D option is installed on the system the button
is shown in the upper right corner of the VOI user interface. When it is activated, the contours are surface rendered as ribbons with a width of the slice thickness. The example shown below is a rendering of the VOIs derived from outlining the AAL template.
In the 3D tool, the VOIs are organized in a tree
so that each structure can individually be shown, hidden and colored. This might be helpful for interactive demonstration purposes to visualize the spatial relationship of the structures.