You can use the Scale manipulator to scale an object from its pivot point. However, if you want to extend or scale an object in a single direction, and not from its pivot point, you can use the Extension manipulator. For example, you can easily extend a cube so that it has a rectangular shape, without having to reposition its pivot point.
The Extension manipulator is a six-arrowed icon. Each arrow extends the object along one side of an axis. The controls at the end of the axes are colored to represent the positive and negative sides of each axis, where a darker color represents positive, and a lighter (pastel) color represents negative. The cube game object in the figure below has its Extension manipulator active.
When you extend an object, you deform it along one axis, making it longer or shorter in that direction. Only the end of the object that you drag extends, however; the other end does not move. You can achieve similar effect by resetting the pivot point and using the Scale manipulator.
In general, the Extension manipulator is most useful for simple objects, such as cubes, cylinders, spheres, and so on. More complex objects are not typically designed to be extended along a single axis and retain visual integrity.
The figure below shows a comparison of using the Scale manipulator (along one axis) and using the Extension manipulator. The pivot point remains at each object’s origin for all three panels. The first panel of the figure shows three cubes. The second panel shows how the Scale manipulator deforms the object along the Y axis, both upward and downward. The third panel shows how the Extension manipulator extends the object in only one direction along the Y axis, upward.
You can also adjust an object’s Scale property and Translation property parameters to specify the amount of extension for an object. You must adjust both parameters because the Scale parameter acts like the Scale manipulator, and scales the object from its pivot point. Thus, after you adjust an object’s Scale parameter, you must adjust its Translation parameter for the same axis by an appropriate amount. For example, to achieve the same result as shown in the third panel of the figure above, you could adjust the cube’s Scale parameter for the Y axis to from 1 to 3 and then adjust its Translation parameter for the Y axis from 0 to 1.
If you extend a group of game objects, each game object extends by the same amount along the selected axis.
If you extend a game object through zero to negative values, the game object inverts.
To extend game objects: