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The mode of operation is similar to “Move” and “Rotate”, but here the object's dimensions are changed. There is also a small cube in the middle of the coordinate axes. When you click and drag the mouse over this box, all axes turn yellow and it is possible to scale the node in all three dimensions simultaneously. The “Scale” tool's shortcut is R.
Axis
This icon provides two different states: global and local. 3D programs also offer the possibility to distinguish between these coordinate systems. When you work in “local” mode, a transformation matrix will be added to the object. An example: Let's say you rotate a cube around two axis in global mode. In this case, each axis points into a certain direction. When you switch to “local” you will see exactly the same setup – there is absolutely no difference.
Now, reset the rotation and repeat the rotation in “local” mode. Again, the three axis have a certain direction, but when you turn on the “global” mode you will see that they have their initial orientation. This way it is possible to introduce a local transformation, for example to create an initial rotation or position, while the global orientation remains the same. When the object is then moved by rigid body dynamics, or a fluid, the rotation and position changes will be performed globally again.