A Tool in VMD is a sensor configured to perform a particular task. The user can move the sensor about in space, and the tool connected to that sensor can then be used to perform an action. There are two types of tools: pointer (the default) or grabber. Each sensor can be configured as a different kind of tool. To make the first pointer into a grabber, select the tool in the browser and choose `grabber' in the chooser. When you want to return to the pointer, choose `previous'. The Length, Scale, Detail, and Offset controls modify the corresponding values in the currently selected tool. Modifying these values changes how the tool is represented graphically, and where it is positioned in space.
