View options

VisIt’sPopup menu andToolbar (see Figure 6-12) have several options that are available for manipulating the view. You can reset the view, recenter the view, undo a view change, toggle perspective viewing, save and reuse useful views, or choose a new center of rotation.

Figure 6-11: Tool menu and toolbar

Box tool Line tool Plane tool Sphere tool Tool toolbar Tool menu Point tool

Figure 6-12: View menu and toolbar

View menu View toolbar

Reset view Recenter view Undo view Perspective Save view Choose center

154 The Popup menu and the Toolbar

5.5.1 Resetting the view

ThePopup menu has aReset view option (see Figure 6-12) that resets the view used to view the plots in the vis window. The view is typically reset to look down the -Z axis in a right-handed coordinate system. You can reset the view by selecting the Reset view option from thePopup menu or by clicking on theReset view icon in theToolbar.

5.5.2 Recentering the view

Sometimes adding a plot to a vis window that already contains plots can result in a lop- sided visualization. This happens when the spatial extents of the plots do not match. The

Popup menu has aRecenter view option (see Figure 6-12) to calculate a new center of rotation for the plots so they are drawn in the center of the window. You can also recenter the view by clicking on theRecenter view icon in theToolbar. To make sure that the view updates appropriately when new plots are added to the vis window, you may also want to check theAuto center view check box that is available in theView

Window.

5.5.3 Undo view

The vis window saves the last ten views in a buffer so that you can restore them if you make an unintended change to the view. You can undo a view change, by selecting the

Undo view option in thePopup menu’s View menu or by clicking theUndo view icon in theToolbar (see Figure 6-12).

5.5.4 Changing view perspective

When the vis window contains 3D plots, the perspective setting can be used to enhance how 3D the plot looks. In a perspective projection, graphics grow smaller as they recede into the distance which makes them look more realistic. To change the perspective setting, click on thePerspective

option in thePopup menu’s View menu (see Figure 6-12). When the vis window uses a perspective projection, the Popup menu’s

Perspective option will have a selection rectangle around its icon. You can also turn perspective on or off by clicking on thePerspective iconin theToolbar. The difference in appearance having perspective and not having it is shown in Figure 6-13.

5.5.5 Locking views

The vis window can lock its view to other vis windows. When this toggle is set, making a change that affects the view in the active vis window will cause other vis windows that have the lock views toggle set to receive the same view as the active window. To lock the view, select theLock view option from thePopup menu’s View menu (see Figure 6-

Perspective on Perspective off

The Popup menu and the Toolbar 155 12) or click on theLock view icon in theToolbar. Note that you can lock 2D and 3D windows separately.

5.5.6 Saving and reusing views

Sometimes when analyzing a database, it is useful to be able to toggle between several different views. VisIt allows you to save up to 15 views that you can then use to look at different parts of your visualization. When you navigate to a view that you like, click the

Save view icon in theView toolbar or click theSave view option in thePopup menu’s Viewmenu to save the view. When you save a view, VisIt adds a new numbered camera icon to theView toolbar and thePopup menu. Clicking on a view icon makes VisIt use the view that is associated with the clicked icon so you have one-click access to all of your saved views. You can preserve the saved views across VisIt sessions if you save your settings. If you want to delete the saved views so you can create different saved views, click theClear saved views icon next to theSave views icon in theView

toolbar.

5.5.7 Fullframe mode

Some databases yield plots that are so long and skinny that they leave most of the vis window blank when VisIt displays them. VisIt provides Fullframe mode to stretch the plots so they fill more of the vis window so it is easier to see them. It is worth noting that Fullframe mode does not preserve a 1:1 aspect ratio for the displayed plots because they are stretched in each dimension so they fit better in the vis window. To activate Fullframe mode, click on theFullframe option in thePopup menu’s View menu.

5.5.8 Choosing a new center of rotation

When you are working with a 3D database and you have created plots and zoomed in on them, you should set the center of rotation. The center of rotation is the point about which the plots are rotated when you rotate the plots in navigate mode. Normally, the center of rotation is set to the center of the plots being visualized. When you zoom way in on plots and attempt to rotate them, the default center of rotation often causes plots to whiz off of the screen when you rotate because the center of rotation is not close enough to the geometry that you are actually viewing. To set the center of rotation to something more suitable, VisIt provides theChoose centerbutton, which can be accessed in thePopup

menu or in theView toolbar. Once you click theChoose center button, VisIt

temporarily switches to pick mode so you can click on the part of your visualization that you want to become the new center of rotation. Once you click on a plot, VisIt exits pick mode and uses the picked point as the new center of rotation. After setting the center of rotation, VisIt will make sure that the picked point is visible at all times.