Let's consider a situation where we have the window symbol that we have used so far with an unknown length of the AB baseline and we want the length of the AB line to become 16 units and the rest of the window should scale proportionally. In this case, you can use the reference option to scale the drawings with reference to any specific length and you can avoid using a scale factor altogether. This method of scaling drawings using a reference is shown in the following example:

1. To use this feature, once again start with the scale tool, select the window symbol that you want to scale, and press the Enter key.
2. Now, the command line will prompt you to specify the base point. Select the A point once again and now, from the command line options, select Reference or type R and press Enter to select the Reference subcommand, as shown:

3. Now, the command line will prompt you to specify the reference length. In this case, the reference is the AB line of the window and if you know its length, type it in and press Enter. Otherwise, click on the point and then the B point and AutoCAD will take that length as the reference length.
4. Now, the command line will prompt you to specify a new length. Type the new length of AB that you want; in this case, type 16 and press Enter.

You will notice that the window will scale so that the length of the AB line on the window becomes 16 units and other lines and arcs of the window will change in size, proportionally.

So, this was all about using Scale command in different situations. In the next section, we will learn to make chamfers on the edges or vertices of different geometries.