QCad User Reference Manual

# 24. Dimensions

This chapter is about constructing dimensions. Figure 36 shows the notation that is used when referring to dimension parts.

Figure 36: Notation for dimensions.

Options Toolbar:

The dimensioning tools may show individual option toolbars, but also share one common toolbar. It allows you to enter a text label for the dimension:

This text label can be any text. When left empty, the label is generated automatically and contains the measured distance (or angle) of the dimension. To add additional signs or letters to a measured dimension, you can use the combination `<>` to insert the automatically generated label anywhere in the text you enter.

Examples:

Chosen label in the toolbar: | Example for the generated label:
`a` | `a`
`<>` | `20`
`<> H7` | `20 H7`
`∅<>` | `` `∅20`

The toggle button with the diameter sign can be used to show a diameter sign before the dimension label. Use the edit field right after that button to enter any text to be displayed as the label. The combo box contains some often used symbols. Select a symbol from the list to insert it into the edit field for the label. The two edit fields at the right are usually used to indicate tolerances. The first for the upper tolerance of a value (e.g. +0.1) and the second one for the lower tolerance (e.g. -0.05). See Figures 37 and 38 for an example.

Figure 37: These example options generate a dimension label as shown in Figure 38.

Figure 38: Example dimension label with advanced options.

## 24.1. Aligned Dimensions

CAD Toolbar:

Menu:

    Dimension - Aligned

Hotkey:

    da

Command:

    dimaligned

Description:

Creates aligned dimensions. Aligned dimensions usually measure the length of an existing line (Figure 39). The dimension line is always parallel to the line between the two extension line endpoints.

Figure 39: Example for an aligned dimension.

Procedure:

1. Set the first extention line endpoint with the mouse or enter a coordinate in the command line.
2. Set the second extension line endpoint.
3. Set the position of the dimension line.

## 24.2. Linear Dimensions

CAD Toolbar:

Menu:

    Dimension - Linear

Hotkey:

    dr

Command:

    dimlin

Options Toolbar:

Description:

Creates linear dimensions. Linear dimensions are usually used to measure vertical or horizontal distances but can also measure distances with any other angle. Figure 40 shows a horizontal version of a linear dimension.

Figure 40: Example of a horizontal, linear dimension.

Procedure:

1. Enter the angle of the dimension in the options toolbar or click the vertical or horizontal button to set the angle to 0 or 90 degrees.
2. Set the first extension line endpoint with the mouse or enter a coordinate in the command line.
3. Set the second extension line endpoint.
4. Set the position of the dimension line.

## 24.3. Horizontal / Vertical Dimensions

CAD Toolbar:

Menu:

    Dimension - Horizontal

    Dimension - Vertical

Hotkey:

    dh, dv

Command:

    dimhor

    dimver

Description:

These tools are provided for convenience and behave essentially like the tool described above (Linear Dimension). The only difference is that you don't have to enter an angle.

## 24.4. Radial Dimensions

CAD Toolbar:

Menu:

    Dimension - Radial

Command:

    dimrad

Description:

Creates radial dimensions for circle or arc entities (Figure 41).

Figure 41: Example of a radial dimension.

Procedure:

1. Choose a circle or arc entity.
2. Set the position of the radial dimension line using the mouse or by entering a coordinate or an angle in the command line.

## 24.5. Diametric Dimensions

CAD Toolbar:

Menu:

    Dimension - Diametric

Command:

    dimdia

Description:

Creates diametric dimensions for circle or arc entities as shown in Figure 42.

Figure 42: Example of a diametric dimension.

Procedure:

1. Choose a circle or arc entity.
2. Set the position of the diametric dimension line using the mouse or by entering a coordinate or an angle in the command line.

## 24.6. Angular Dimensions

CAD Toolbar:

Menu:

    Dimension - Angular

Command:

    dimang

Description:

Creates angular dimensions between two reference lines as shown in Figure 43.

Figure 43: Example of an angular dimension.

Procedure:

1. Choose the first line entity.
2. Choose the second line entity.
3. Set the position of the angular dimension line using the mouse or by entering a coordinate in the command line.

## 24.7. Leaders

CAD Toolbar:

Menu:

    Dimension - Leader

Hotkey:

    dl

Command:

    dimlea

Description:

Leaders are arrows that usually point from a text entity to an other entity as shown in Figure 44. In the example, the text entity "N7" is describing a surface property by pointing to it with a leader.

Figure 44: Example of a leader.

Procedure:

1. Set the location where the leader points to or enter a coordinate in the command line.
2. Set the location of the next edge of the leader line.
3. Set the other edges of the leader line and press Return or click the right mouse button to finish.