Dimensioning a Drawing

Dimensioning a drawing is perhaps the most important step in creating a technical drawing. Dimensions allow you to accurately convey information on your design to the reader. As you begin to dimension your drawing, you will find they are only as accurate as the drawing you create. Properly set up and applied, AutoCAD can allow you to easily and accurately dimension your drawings.

The objectives of this assignment are:

  1. Understand dimensions and their use. In this unit you will look at the majority of the AutoCAD dimensioning commands. You will begin by covering some basic dimensioning terminology. While the placement of dimensions is very important, it is beyond the scope of this course to describe how to properly dimension a drawing. Both the ANSI and AIA provide commercial standards for dimensioning. It is important that you learn any standards necessary in your particular discipline and apply them to the AutoCAD dimensioning commands.
  2. Understand the importance of associative dimensioning. By default all dimensions you create in AutoCAD are considered associative. This means that all objects that make up the dimension are grouped into one object. This has many advantages, and some disadvantages as well.
  3. Create and use dimension styles and families. Dimensions styles and families are a way you can save specific dimensions settings.
  4. Modify existing dimensions. One very important point to remember when dimensioning a drawing with AutoCAD is just because AutoCAD created a dimension in a specific manner, it does not mean it is correct. Often you will have to modify a dimension, or even create a dimension manually (draw separate lines, arrows, text, etc.)
  5. Create oblique dimensions and leader. These are two types of dimensions commonly used in AutoCAD for dimensioning.


  1. Read Unit 13, Dimensioning a Drawing. This unit was intentionally written in a generic format - not geared specifically toward any one discipline. In the optional assignments you will have the opportunity to create specific dimensions styles and apply apply them to mechanical and architectural drawings.
  2. Complete Tutorial 13.1 - 13.3. In this set of tutorials you will open up a sample drawing, and work with several of the dimensions settings.
  3. Complete Tutorial 13.4 - 13.8. In these tutorials you will apply different types of dimensions to the sample drawing.
  4. Complete Tutorial 13.9. Here you will modify a dimension, and add a leader.
  5. Unit 13 tests from the Testing Website. Complete the following tests and E-MAIL me the results.
Forum Home Page Remember that just because AutoCAD creates a dimension a particular way does not mean it is correct. You still need to know proper dimensioning practices. Does AutoCAD dimensioning help, or does it make it too easy to create incorrect dimensions? Post a question or comment on this unit in the forum.

What to Turn In:

E-MAIL me the following:

  1. The completed DIMENSION.DWG file from tutorials 13.1 - 13.8.

Architecture Assignment

In the optional architectural assignment, set up a dimension style specifically for architectural drawings. You will then use this style to dimension the floor plan you have been working on in the past several units.

    Dimension the Floor Plan

Mechanical Assignment

The optional mechanical assignment creates two dimension styles, one for US Customary units, and the other for Metric (SI) units. You will then apply these dimension styles to the metric Micro Stop and the Worm Gear which you created in the previous units.

    Dimension the Micro Stop.

    Dimension the Worm Gear.

Electrical Assignment

The optional electrical assignment you will download and dimension two different drawings. One drawing uses the US Customary units, and the other Metric (SI) units. After downloading and dimensioning these drawings, E-MAIL them.

    Dimension the Circuit Board Mount.

    Dimension the C-CLAMP.