1. UNIT 8: Dimensioning In AutoCAD
Objectives:
Be able to identify, describe and/or apply…
Methods for accessing the layers properties manager
Assignments/Quizzes/Tests

2. UNIT 8: Dimensioning In AutoCAD
Basic Concepts with Dimensioning
Are “Annotations” you add to drawings to show size
Should be placed on separate layer
Each dimension has its own “Style”
Each dimension you create consists of several parts:
Dimension Line
Extension Line
Arrowheads (Can be modified or changed)
Dimension Text
Precision (Number of decimal places)

3. UNIT 8: Dimensioning In AutoCAD (Types of Dimensions)
Linear
Aligned
Radius
Linear
Diameter
Arc Length

4. UNIT 8: Dimensioning In AutoCAD (Types of Dimensions)
Jog lines can be added to linear dimensions. Jog lines are used to represent a dimension value that does not display the actual measurement. Typically, the actual measurement value of the dimension is smaller than the displayed value.
The jog is made up of two parallel lines and a cross line that forms two 40-degree angles. The height of the jog is determined by the linear jog size value of the dimension style.
Once you add a jog to a linear dimension, you can position it by using grips. To reposition the jog, select the dimension and then select the grip. Move the grip to another point along the dimension line. You can also adjust the height of the jog symbol on a linear dimension on the Properties palette under Lines & Arrows.

5. UNIT 8: Dimensioning In AutoCAD (Types of Dimensions)
Ordinate dimensions measure the perpendicular distance from an origin point called the datum to a feature, such as a hole in a part. These dimensions prevent escalating errors by maintaining accurate offsets of the features from the datum.
Ordinate dimensions consist of an X or Y value with a leader line. X-datum ordinate dimensions measure the distance of a feature from the datum along the X axis. Y-datum ordinate dimensions measure the distance along the Y axis.
The location and orientation of the current UCS determines the ordinate values. Before creating ordinate dimensions, you typically set the UCS origin to coincide with the datum.

6. UNIT 8: Dimensioning In AutoCAD (Changing The Precision)
Select “More Arrow” in dimensions panel
Select “Modify”
Under the “Primary Units” tab select “Precision”

7. UNIT 8: Dimensioning In AutoCAD (Types of Dimensions)
Associative or Standard Dimensions
Associative or Standard dimensions Automatically adjust their locations, orientations, and measurement values when the geometric objects associated with them are modified.
NOTE: Never explode a dimension. It will break into separate parts and will NO LONGER be associated or attached to the object.

8. UNIT 8: Dimensioning In AutoCAD (Types of Dimensions)
Annotative Dimensions
Annotative dimension styles create dimensions in which all the elements of the dimension, such as text, spacing, and arrows, scale uniformly by the Annotation Scale.
An Annotative Scale is a setting that is saved with model space, layout viewports, and model views. When you create annotative objects, they are scaled based on the current annotation scale setting and automatically displayed at the correct size.

9. UNIT 8: Dimensioning In AutoCAD (Dimension Rules)
Dimension lines should be spaced uniformly approximately .375” to .5” Always place shorter dimensions nearest to the object lines. Dimension lines should never cross. Dimensions should line up in chain fashion, and never repeat.
Extension lines should have No gaps were lines cross over object lines or other extension lines
Leader lines are always drawn at an angle, never vertically or horizontally

10. UNIT 8: Dimensioning In AutoCAD (Dimension Rules)
Dimension lines should be spaced uniformly approximately .375” to .5” Always place shorter dimensions nearest to the object lines. Dimension lines should never cross.
Extension lines should have No gaps were lines cross over object lines or other extension lines
Leader lines are always drawn at an angle, never vertically or horizontally

11. UNIT 8: Assignment 8-1 (Basic Dimensions)
Using the dimensions rules discussed and reviewed in class complete the drawing to the right using standard dimensioning practices.
Set precision to 0.00
Place dimensions on separate layer labeled “Dimensions.”

12. UNIT 8: Assignment 8-1 (Ordinate Dimensions)
To create ordinate dimensions
Click View tab…..Coordinates panel…..Origin.
At the Specify New Origin Point prompt, specify an origin point.
The origin point specified is used to define the value assigned to the ordinate dimension. Typically, the origin point is defined on the model.
Click Home tab…..Annotation panel…..Dimension drop-down…..Ordinate.
If straight ordinate leaders are required, turn Ortho mode on.
At the Select Feature Location prompt, specify a point location.
Enter x (X Datum) or y (Y Datum). You can skip this step by making sure that the ordinate leader endpoint is close to vertical for an X datum or close to horizontal for a Y datum.
Specify the ordinate leader endpoint.

13. UNIT 8: Assignment 8-2 (Ordinate Dimensions)
Dimension the drawing to the right using “Ordinate” dimensioning practices.
Set precision to 0.00
Place dimensions on separate layer labeled “Dimensions.”
Set as 0,0,0 origin