Classes and Scalar Information

The Classes and scalar information box, shown below, indicates the name of each class in the multi-ROI, the number of labeled voxels, and the color assigned to each class. If available, you can also view scalar information related to each class. You can show or hide any class by toggling the visibility control, as well as set a class as the background. In addition, a Pick tool is available for visually selecting a class in a view.

Classes and scalar information


The following items and options are available in the Classes and scalar information group box for a selected multi-ROI:

Classes and scalar information




Lets you show or hide the colored highlight applied to the labeled voxels within a class.


Is the color of the highlight that is applied to the labeled voxels within a class.

Note The opacity of the highlight is adjustable with the sliders in the 2D opacity and 3D opacity boxes..


Lets you adjust the opacity of each labeled class independently. Click the Opacity icon in the classes list to open the Opacity slider, as shown below. You can then adjust opacity from 0 to 100 percent with the slider.

Note Whenever you change the opacity of a class, the global opacity settings selected in the Opacity and color box will not be applied. However, you can right-click a class with an individually set opacity and then choose Use Global Opacity in the pop-up menu to reinstate the global opacity settings.


Is the name assigned to a class.


Is the total number of labeled voxels in a class.


Indicates the label number assigned to each class or the selected scalar information (see Scalar Information).


Lets you visually select a multi-ROI class or multiple classes by picking in a 2D or 3D view.

  • Hold down Left Shift and then click to select a multi-ROI class in a view with the Pick tool.

  • Hold down Left Ctrl and then click to select multiple multi-ROI classes in a view with the Pick tool.


Lets you add one or more classes to the multi-ROI as follows:

Add Class… Automatically adds a new class to the multi-ROI.

Add Multiple Classes… Lets you choose the number of classes to add to the multi-ROI.


Deletes the selected class.


Merges the selected classes.

Note The class name and color of the merged class are whose associated with the class you selected first and that is identified as 'A'.

Background class

If enabled, labeled voxels that are removed from any class, as well as unlabeled voxels that are painted, will be added automatically to the set background class (see Setting a Class as the Background).

Labeled voxels count

Indicates the number of labeled voxels in the selected class.

Scalar information Measurements that were computed for the selected multi-ROI, imported from a file, or copied from another object, are available in the Scalar information group box (see Scalar Information).

* Available for single selections only.
** Available for multiple selections only.
*** Available for two selections only.