Although decimal drawing units are the most commonly used, you can configure AutoCAD to work with other types of drawing units. To change the unit type, you must use the Drawing Units dialogue box. When you start the Units command, the first thing you see is the Drawing Units dialogue box, shown on the right. The dialogue box is divided into four main sections. The upper two are "Length", which refers to linear units and "Angles", referring to angular units.
Settings for linear units and angular units can be made independently and in each case, you can control both the type and precision. In addition, the Angles section also allows you to specify the direction in which angles are measured.
See below for more details. A third section, entitled Drawing units for Design Center blocks allows you to assign a specific unit to the drawing so that when blocks are inserted via the AutoCAD Design Centre, they will automatically be scaled.
The final section, Sample Output, gives you a preview of the drawing units as they will be displayed using the current settings. You can see from the dialogue box that there are five different linear unit types for you to choose from, one of which is "Decimal", the default.
The table below shows the effect of the different unit settings on two drawing unit values to give you an idea how the various settings might be used along with a brief description. Notice that when you change the unit type, the co-ordinate display on the status bar changes to show co-ordinates using the current unit type. Changing the unit type also affects the way distances, areas and volumes are reported when using the appropriate inquiry command.
For the most part you should not need to change the unit type. Looking at the Drawing Units dialogue box again, you will notice that there are also five angular unit types. The default is decimal degrees, but there are other options. The table below shows the effect of the different unit types on two angular unit values.
Making a change in units early in your work can save you from unnecessary adjustments later on. Check out our guide on how to change units in AutoCAD.
This applies to both length measurements and angles, allowing you to work with models at different scales and at the level of precision you require. This includes measurements shown in the status bar, the numbers you input in the command line, and any area or volume calculations you make.
For instance, using units that are precise to the 6th decimal point is a poor choice for architectural work that does not require this level of precision. On the flip side, small engineering projects might benefit from more precise measurements.
To be able to optimize the different options for units offered by AutoCAD, you need to know the difference of each category from the others and how and when they are appropriate for use. The length unit options available in AutoCAD are as follows:. These units use feet and inches, plus any fractions of an inch if necessary. As the name implies, these units are commonly used for architectural works or any component that is measured at an architectural scale.
This is essentially a unitless unit, which is a seemingly paradoxical definition. However, it only means that a measurement made in Decimal mode can be used to conform to any unit of your choosing. As long as the relative dimensions of each part of the model are accurate to your liking, then you can choose to scale it from an inch to a kilometer later on. Used for engineering applications, engineering units also use feet and inches as base units. The only difference from the Architectural system is that Engineering units represent fractions of an inch as a decimal number.
To demonstrate, three and three-quarters of an inch will be displayed as 3. To scale an object, specify a base point and a scale factor. A common method of determining volumes from cross sections is that of average end areas. It assumes that the volume between successive cross sections is the average of their end areas multiplied by the distance between them.
This is expressed in the formula: V Ft. The cut factor is used to adjust the volume of excavated material to account for the amount you expect the material to swell when it is excavated. The fill factor is used to account for the additional volume of material that would be required due to the compaction of the soil when it is placed.
The user coordinate system UCS establishes the location and orientation of a movable Cartesian coordinate system. The UCS is an essential tool for many precision operations. The UCS defines. The horizontal and vertical directions used for features like Ortho mode, polar tracking, and object snap tracking.
To see the number of blocks type BCOUNT on the command line and press enter then select an area in the drawing from where you want to count blocks. With no command active, right-click in the drawing area and choose Quick Select. Click the Quick Select button in the Properties palette. Type qselect on the command line. There are a few ways to get that information: Use the Insert command. All blocks in the current drawing will be listed in the pulldown. Use the BEdit block edit command. All blocks in the current drawing will be listed in the selection box.
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