Setting units

When you start a drawing with any template shown in figure 1.20, you will have some predefined unit settings, which we will modify now.

For this example, select the acad.dwt template from the start panel and a blank drawing will open up.

Type UN and press Enter to open the unit window. Alternatively, you can also click on the application button and select the Drawing Utilities option and then Units from the next menu:

The Drawing Units window is divided into several panels, such as Length, Angle, Insertion scale, Sample Output, and Lighting. Let's talk about these options in the Drawing Units window:

In the Length panel, the drop-down window has many different length types, such as Architectural, Decimal, Engineering, Fractional, and Scientific. You can select Decimal from these options if you want a simple decimal type output, such as 12.2345 or 245.01289.

The Architectural length type will show output in the form of feet and inches, such as 12’ 6”, where 12 is in feet (shown with the single apostrophe sign) and 6 is in inches (shown with the double apostrophe sign). The Architectural format can be used when you want to enter the length in terms of feet and inches, and it's mostly useful for civil and architectural drawings.

Other formats will have their respective representation types and you can select any from the list, as per your drawing and project requirements.

The next option of Precision controls the number of decimal places that will show in the drawing. This precision is not the precision with which AutoCAD calculates the dimensions. Instead, it’s the precision that is displayed on the drawing. AutoCAD will always measure your drawing with maximum possible precision, no matter what precision you select in the Drawing Units window.

Just like the length type, the settings for the angle can be managed from the Angle panel. Here, you can select between Decimal Degrees, Degree/Minute/Second, Grads, Radians, and Surveyor’s Unit. The precision is again the number of decimal places for the angle that will be displayed on the drawing.

In AutoCAD, the angle is measured in an anticlockwise direction and hence, anticlockwise is the positive angle. If, however, you want to make a clockwise direction the positive angle, click on the checkbox that says Clockwise in the Angle panel:

From the Insertion scale panel, you can change the unit type of the current drawing. All the drawings inserted from external files will be scaled to this selected unit no matter what the unit of the original drawing is.

There are lots of units in this list and you can even select the Unitless option from the list if you don't want to use any unit in the drawing.

Finally, the Lighting panel has two options: American and International. You can select one of the options from this list. The Lighting option will be used in the rendering section of chapter 16 and it has no application in the 2D drawing environment.

So, after setting the settings, click OK and the settings will be applied to the current drawing.

In this case, I am selecting the Decimal Length type with a 0.00 length precision and the Decimal Degrees angle type with a 0.00 precision. I will leave the Clockwise checkbox unchecked. In the Insertion scale panel, I will select Millimeters and International in the Lighting section. These settings are also shown in figure 1.22.

So, now we are done setting the unit settings, let's move on to setting the limits of our drawing area. We will discuss this in the next section.