---
title: "Label/Edit tools"
canonical: "https://help.vicon.com/space/Nexus215/11376204/Label%2FEdit%20tools"
format: markdown
---
The **Label/Edit Tools** pane enables you to manually label trial data and fill any gaps in trial data. It contains the following sections:

- **Subject** You select the subject to manually label or edit in the **Subject** list at the top of the **Label/Edit Tools** pane. To appear in this list, the subject's node must be selected (ie, its check box must be selected in the **Subjects** tree in the **Resources** pane).
- **Manual Labeling** You manually label reconstructed trial data for the selected subject using the controls in this section. For instructions, see [ ](https://vicon-help.atlassian.net/wiki/spaces/Nexus215/pages/11371686)*[Manually label a trial](https://vicon-help.atlassian.net/wiki/spaces/Nexus215/pages/11371686)*[ ](https://vicon-help.atlassian.net/wiki/spaces/Nexus215/pages/11371686) in the *Vicon Nexus User Guide*.
- **Backward**, **Whole**, and **Forward** buttons. Label the currently selected trajectory either for the whole trial, or backward or forward from the current frame. Use **Whole** if you are confident that the trial data contains very few mislabels or swaps. Use **Backward** or **Forward** to label the trial data backwards or forwards from the current frame, without affecting other frames.
  :check_mark: **Tip**   
When you are manually labeling a subject, to help you place the selected label onto the correct 3D reconstruction, in the **3D Perspective** view pane the pointer changes to include a tooltip that identifies the label. You can also use the **Subject Viewer** to help you identify the markers (see [Subject Viewer](https://vicon-help.atlassian.net/wiki/spaces/Nexus215/pages/11380192)).
- **Auto advance selection** When selected, Nexus automatically advances to the next marker in the **Manual Labeling** list. Default: Selected
- **Find Next Unlabeled Trajectory** When you click this button, Nexus advances to the next frame that contains an unlabeled marker trajectory.
- **Swap Marker Labels** To correct swapped marker labels, select the relevant two marker trajectories and then click this button.
- **Gap Filling** Enables you to identify and fill gaps in reconstructed marker trajectories. See also the FAQ *What gap-filling algorithms are used in Nexus 2?* on the [Vicon website](http://www.vicon.com/faqs).