Autodesk 00126-050008-1640A User Guide - Page 122

9 Working with Raster Selection Raster Selection Composition During selection the raster data is placed in a temporary buffer, called a raster selection set. The selecting process may consist of an arbitrary number of steps. This procedure is called raster selection set composition. A raster selection set can be composed from parts of various images. You can select data from one image, complete the selection, and then skip to another image and continue selecting. Raster selection is an independent procedure for each image. All raster data, selected on different images, is placed on a separate raster image, created during the selection. This image is called a raster selection set. If you make selection consequently on several images, then all raster selection sets, created on different images, are combined into an AutoCAD group. After selection is completed, this allows manipulating all the selected raster as an entire AutoCAD object. You can create a raster selection set in a few steps. As usual, you can first select a single raster object, and then add some more objects to the selection set, and after that remove some of the previously selected raster data from the selection. The current Selection mode defines if a raster part selected at the current step of raster selection composition is removed or added. Selection Set Composing Modes There are three modes of composing a selection set: Add, Remove and Single. Single Selecting data in Single mode deselects all previously selected data in the current image. With Single turned on, the selection set in the current document consists of the data selected during the latest selecting step or of nothing. To turn Single mode on, click the button on the Raster Selection toolbar. With the SHIFT button pressed, Single mode turns to Add mode. Add Raster data selected in Add mode is added to the current selection set. To turn Add Mode on, click the button on the Selection toolbar. In Add mode composition of selection set can consist of several steps, every step being a single selection operation. On every step you can vary the selection methods. With the SHIFT button pressed, Add mode turns to Remove mode. Remove Use Remove mode to remove selected data from the selection set. To turn Remove mode on, click the button on the Raster Selection toolbar. With the SHIFT button pressed, Remove mode turns to Add mode. Usually you first select a single object, and then add some more objects to the selection set, and after that remove some of the previously selected data from the selection. Data can be removed from the selection set using the same methods as 125