OpenWalnut Help


  1. Introduction
  2. First Steps
  3. Main Window
  4. Navigation
  5. Keyboard Shortcuts
  6. Toolbar
  7. Regions of Interest
  8. Customizing OpenWalnut


The intention of this help document is to give a short overview of how to use the current version of OpenWalnut. Although it is not at all comprehensive, it provides a description of the most commonly used features and GUI elements. As described below, the appearance of the GUI is customizable. This help document assumes the standard configuration. Additionally, some described features may not be available in every instance of OpenWalnut because they belong to special modules.

First Steps

This tutorial shows you the basic useage of OpenWalnut. You should consider reading this if you are a first time user.

Main Window

This is the main window of OpenWalnut. It is divided in three parts. The navigation views, the main view and the data manipulation GUI.


Navigation in Main View

Mouse Button  Action
RightPick, move ROI box, or move slice
Right + [Shift]Resize ROI box
+Zoom in
-Zoom out
[Space]Reset view

Navigation in EEG View

Mouse ButtonAction
LeftMark event position
RightZoom in time
WheelScale voltage
Wheel + RightChange spacing between graphs
Wheel + LeftChange sensitivity of the coloring of the head surface

Keyboard Shortcuts

Program-wide Keyboard Shortcuts

[Ctrl] + qQuit
[Esc]Resets main view
[F1]Opens help window

ROI tree

[Delete]Removes ROI

Module tree

[Delete]Removes module


Load DataLoads data given in various formats like fibers (.fib), NIfTI images (.nii, .nii.gz) or EEG data (.cnt). Not all supported file formats are available through this button and the dialog behind it. For some file formats there are special modules for reading and/or writing them.
Load a project from fileOpens a project file (.owp), and instantiates modules, sets their connections and orients the scene accordingly.
Save current project to fileSaves the current state (modules, connections, orientation of the scene) of OpenWalnut to a project file (.owp).
Reset main viewRotates and scales the scene in the central 3D view to show the same orientation as after program startup but zoomed to show all contents of the scene.
Create new ROI boxAdds a new ROI box to the 3D scene and the ROI browser. See also: ROIs.
Missing module?This opens the dialog that allows to customize the list of modules that are allowed to appear in the Compatible Modules toolbar.

Regions of Interest

A ROI (region of interest) is usually used to specify a certain area (2D) or volume (3D) that can then be accessed by modules. Different modules will use ROIs for different purposes. The most important purpose of ROI boxes in OpenWalnut is the selection of fibers in conjuction with fiber display modules. It will be described in a separate section below. The ROIs can be moved around by dragging them with the right mouse button. Their size can be changed by dragging one of their faces with the right mouse button while the [Shift] key is pressed.

ROIs for selecting fibers

For the special task of selecting fiber bundles from larger sets of fibers ROIs can be combined in the ROI tree widget. All ROIs in the same branch of the tree are combined using a Boolean "and" operation. The result will be a bundle consisting only of fibers that pass through all boxes in the branch. The branches themselves are combined using a Boolean "or" operation. This means that the bundles selected by the different branches will be visible/selected at the same time.

Customizing OpenWalnut

OpenWalnut allows you to configure several features. Most of these options are only useful to advanced users. Have a look into the View, Camera and Settings menus for what you can adapt. If you would like to configure which modules are allowed to be shown in the toolbar click on the Missing Module? button with the three question marks. The appearing dialog will provide enough information and the possibility to customize which modules may appear. This can be useful to maintain a not too crowded toolbar.

For more information on OpenWalnut visit