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Dimensions in AutoCAD. How to set, change, scale dimensions in AutoCAD? Dimensions in AutoCAD - everything you need to know How to make your own style dimensions in AutoCAD

21.09.2023

The task of how to adjust dimensions in AutoCAD is dual in nature. You can adjust a previously set size - you are not satisfied with its size or geometric characteristics; or create a new size style and use it in the future as a kind of library of sizes of a very different nature.

We also keep in mind one more nuance, taking into account which can be very helpful in real work. The fact is that there are a great many situations and not everything can be foreseen. In other words, not everything can be included in the dimension style being used. Therefore, the developer must be ready, if necessary, to create a dimension “manually” - AutoCAD provides all the tools for this - there are lines, arrows, text tools, and the ability to use special symbols (problems often arise with setting diameters and radii according to the requirements of our GOSTs) .

In addition, let’s not forget that when choosing a value, the program is guided by real dimensions that correspond to the selected drawing limits. In other words, setting dimensions in AutoCAD necessarily occurs after going to the “Format” / “Drawing Limits” menu. This is fundamentally important for AutoCAD - all work and display takes place with real dimensions, the developer is freed from the need to first take a measurement, then convert it into points on the screen, and then enter it into the parameter of the object being depicted. Such work “the old fashioned way” is a thing of the past.

Setting the created size

When a dimension is set, it exactly matches the general parameters specified in the current working style for the given dimension type. But the general settings do not always reflect the desired size parameters; to change them, you can use the size’s context menu to call its properties (in the menu window - “Properties”).

The properties window can also be called up through the main menu using the “Modify” / “Properties” command, using the “Properties” tool on the main toolbar or using the hotkey combination - “ Ctrl+1".

Among the many possible local changes that can be made (appear immediately after the change):

Color - change the color; by default, the color assigned to the layer is selected;
Layer - move the size to another layer; In general, it is useful to place all dimensions on a separate layer, but if you make a mistake with this data, then it is possible to transfer it;
Dim style - change the style to which the size belongs;
Lines & Arrows - a group of “small” settings for the geometry of lines, all possible indents and the type of arrows;
Text - group of text settings - format, position, indents. Please note that by default AutoCAD sets the actual size within the limits of the drawing (indicated in a pale color in the Measurement parameter), but this value can be changed if necessary (after all, if a sketch is created, the main thing is that the dimensions are correctly set and that the graphics correspond to them not at all necessary). You can change the measured value using the parameter included in this group - Text override. In practice, this is one of the most frequently performed configuration tasks.
Fit - a group of options for the relative position of lines, arrows and text, if the object being measured does not allow you to set the size in a standard way - another group of frequently used settings.

Working with Dimension Styles

As a matter of fact, when they talk about setting sizes in AutoCAD, they mean a dimensional style - a library of sizes of different types, created according to the requirements, for example, of one standard.

Initially, the program uses one built-in style by default - ISO-25 (indicated in the "Dim Style Control" drop-down list located on the "Dimension" toolbar). This panel is not displayed on the screen by default, so the user will need to do it himself (command “View” / “Toolbars”).

Please note that the user is given the opportunity, if necessary, to first create a dimension in one style, and then change it by selecting it in the list of styles - this way it turns out that all dimensions of the drawing are in one style, and one in another, this is a common situation.

Working with styles is done using the “Dimension Style” command, which by default is located to the right of the list (here, as in any program, the user has the right to change both the presence of the command in the panel and its location).

When you start working with styles, you have at your disposal:

Styles - list of available styles;
List - select the option for forming a list - all styles or only used ones;
Set Current - setting the style selected in the list as the current working one;
New - creating a new style based on the one selected in the list;
Modify - change the style;
Override - style override;
Compare - comparison of two styles (a very useful command when you have to work with an unfamiliar drawing).

When creating a new style, you are prompted to pre-select not only the initial style, but also the types of dimensions that will be created. By default, it is proposed to configure all types, but the selection includes only linear, radius, diameter, angular, and leader types.

After the choice has been made, when you press the “Continue” button, the developer has at his disposal a window with six tabs, which provide all possible settings. If any of the parameters are not entirely clear, the user will never have problems understanding it - all changes are immediately reflected in the preview window.

Among the most significant settings:

If you have the 2015–2017 version of AutoCAD at your disposal, then the drop-down list of dimensional styles is located here in the “Annotation” panel.

As you can see, setting the sizes is quite a troublesome task - several dozen different parameters - but on the other hand, it’s also fascinating, everything is organized very conveniently, the purpose of each is either described or immediately reflected in the example after use.

This is not to say that you have to create new size styles often; usually the default one - ISO-25 - is quite sufficient, but in particularly “delicate” situations you cannot do without size settings, and you must remember about them.

Dimensions- an important detail in the drawing. Therefore, I decided to write this article about what dimensions are in AutoCAD, how to set and change dimensions.

A dimension in AutoCAD is a complex object that is treated as a single entity. It consists of extension lines, a dimension line with arrows (or tick marks), and a dimension value.

All sizes are fundamentally divided into two groups: linear and angular. Linear dimensions characterize such parameters as length, width, thickness, height, diameter, radius. Angular size characterizes the magnitude of the angle.

Rules for applying dimensions.

These rules in our country are regulated by GOST 2.307-68. So you can go there for the rules for applying sizes. I advise you to adhere to these rules, even if you are not a professional designer or engineer.

Now I will just focus on how to put certain dimensions on drawings in AutoCAD.

On “Annotations” tab on “Size” panel click on button “Linear dimension”. As you probably already know, AutoCAD has special commands for calling tools. In our case this is the command “RZMLINEAR”. Try entering the first letters of the command into the command line, for example, "RZML". The command will be added to the command line itself. Now press “Enter”.

A corresponding prompt will appear on the command line: “Start of first extension line or<выбрать объект>:". Click LMB to select the first dimension point on the object, then the second.

After this, the command line displays the prompt: “Dimension line position or [MText/Text/Angle/Horizontal/Vertical/Rotated]:”. Those. Now you need to indicate the location of the dimension line. According to GOST, this value is 10mm.

Simply moving the cursor approximately to the place where the size should be located, enter the value 10 from the keyboard. You will see how this value is displayed in the number field. Now don't forget to press “Enter”.

For faster work, you can not specify size points, but specify the part of the object that you want to measure.

To do this, in response to the first request, indicate the beginning of the first extension line, simply press “Enter”. You will use the “Select object” option.

Now you need to specify the object for which you need to size. For example, I'll indicate an interior wall. And now, moving the cursor away from the object, a linear dimension follows it. Here the position of the dimension line is arbitrary. Therefore, click LMB anywhere.

Always pay attention to the prompts that appear on the command line. After all, almost every command in AutoCAD has its own options.

Options that can be used when applying dimensions.

After placing the second point of the dimension - this is the beginning of the second extension line, a number of options appear on the command line - MText, Text, Angle, Horizontal, Vertical, Rotated.

Let's look at the sizing options available when using these options.

"MText". This option opens an editor that allows you to edit dimension text.

Here you can change the size value itself. Or add symbols “+-”, “~”, etc. to the value.

"Text". This option allows you to edit dimension text on the command line (without calling the editor). The resulting size value is displayed in angle brackets.

Enter a new numeric value at the command line. You can also change the text in the number field. After entering the value, specify the position of the dimension line.

"Corner". Allows you to change the rotation angle of dimension text.

To set up linear units, follow these steps:

1. Launch AutoCAD, select the command from the menu File » Close or press Ctrl+F4 to close the default drawing, and then use the command File » Create or by pressing Ctrl+N to create a new drawing based on the acadiso.dwt template.

2. Select a command from the menu Format » Units or enter the command in the command window Units or simply units. In the dialog box that opens Drawing Units(Fig. 3.1) make sure that in the list Format groups Linear item selected Decimal, and in the list Format group Corner) - paragraph Decimal degrees.

Rice. 3.1 Dialog window Drawing Units

3. Since when designing the work area of the children's room we will use the metric system of units, leave in the list Format groups Linear selected value Decimal, since everyone else ( Architectural, Engineering And Fractional) use non-metric units (feet, inches and fractions thereof). Selecting a value Scientific leads to the fact that all sizes will be indicated in the so-called scientific format (for example, the value 2.0039 in this format looks like 2.0039E+00), which in our case is not very convenient. To understand the differences between the different types of unit systems, try selecting another value from the list Format and take a look at the examples provided in the area Example. To return to metric units, select again Decimal.

4. Now notice the two drop down lists Accuracy who are in groups Linear And Corner are under the lists Format. Click on the expand list button Accuracy in Group Linear. A list will open and list the acceptable precision values for the unit system Decimal(Fig. 3.2).

Rice. 3.2 Dropdown list Accuracy for system of units Decimal

Note. Drop-down lists are controls that display the current item when collapsed. After clicking the expand list button (it has a downward-pointing triangle), the entire list is displayed on the screen, allowing you to select another item from it. Once selected, the list closes and only the selected item is displayed. As with radio buttons, you can only select one item from a drop-down list.

5. The accuracy specified using this list only affects the accuracy of the representation of linear dimensions in the AutoCAD drawing. If the precision is 0.1, then any line whose length is specified with a higher precision (for example, 2.0039) will be displayed rounded to 0.1 (in our example to 2.0). However, the line will actually have a given length of 2.0039. If you change the precision value to 0.0001 and then use the command Length(discussed in the material in Chapter 7) to determine the length of the line, the measurement will show a length of 2.0039.

6. Select from the list Accuracy point 0.0 to represent linear dimensions with an accuracy of 0.1 mm.

Linear size

Measuring angles

Basic and related sizes

Size style

Dimensioning drawings is perhaps one of the most controversial aspects of working with AutoCAD. While creating dimensions is fairly easy, managing their appearance and behavior can be quite challenging. The reason for this is that there are many different types of sizes and many variables that control their appearance.

Additionally, the way you work with dimensions, their appearance and behavior can vary greatly depending on the industry you work in (mechanical engineering, nuclear power, electronics, etc.). In this chapter, you'll learn how to place dimensions and how to use dimension styles to control their appearance and behavior.

Dimension control commands can be launched using the corresponding buttons on the tab Annotate(Abstract) in group Dimensions(Dimensions) of the tape (Fig. 5.1).

Rice. 5.1. Dimensions group

There are many types of dimensions available in AutoCAD. The most commonly used linear dimensions are radius, diameter and angular dimensions.

Dimensions are associated with objects and are updated automatically when any changes are made to the drawing.

The first step is to select the type of dimension you want to create, and then specify the points that determine its placement. At the specified locations, AutoCAD creates point features, then measures the distance between those definition points and uses that distance as the default text dimension value.

For example, to measure a line, you create a linear dimension and then specify the two extreme points of the line. The program creates defining points in these places and measures the distance between them. After that, you choose a place to place the size value.

Defining points control the associativity of the dimension. When their position changes, the size associated with them is updated and moves to follow them. During dimensioning, AutoCAD automatically creates a level or layer called Defpoints(Defining points). All defining points are placed on this layer.

Note
The Defpoints layer is created when you run the dimension command. It is unique in that it does not print regardless of the print/don't print setting. Once created, the Defpoints layer cannot be deleted using the PURGE command or by clicking the Delete Layer button. You can rename this layer, but then AutoCAD will simply create a new Defpoints layer when you create a new dimension or update an existing one.

Advice
Because the Defpoints layer doesn't print, you can use it to create features that you don't want to show in your drawing. For example, this could include markups, viewing boundaries, and notes for other users working with the drawing.

There are actually three levels of associativity for size. The DIMASSOC system variable indicates what level of associativity is currently in use.

The DIMASSOC system variable can be set to 0, 1, or 2. When set to 2 (the variable's default state), dimension definition points are associated with drawing objects. For example, if you specify the distance between two extreme points of a line, AutoCAD will create defining points there that will be associated with the line object. As you move the line, the dimension will move with it. If the position of the end point of a line changes (the line stretches, shortens, changes direction, etc.), the defining point associated with it will also move and the size will be updated.

When the value of the DIMASSOC variable is 1, AutoCAD still creates associative dimensions, but the definition points are not associated with any specific geometry. To change the size, you must move the defining points associated with the size explicitly. For example, if you specify the size of a line when DIMASSOC is set to 1, AutoCAD will create defining points at the ends of the line. But if you move the line, the size will not follow it. You must select and move the dimension along with the line so that they appear together. If you move the end of a line (by dragging, adjusting, extending, etc.), you should also move the defining point to update the size.

If DIMASSOC is set to 0, AutoCAD creates detached dimensions without associativity or defining points. Each part of a dimension leader (lines and value) is treated as a separate object.

Advice
Although it is possible to create isolated dimensions, this is considered bad practice in most CAD work environments. Isolated dimensions are difficult to manage and updating them can lead to sloppy and inaccurate drawings.

You can change the values of the DIMASSOC variable using the checkbox in the area Associative Dimensioning(Linked Dimensioning) tab User Preferences(Custom Settings) windows Options(Parameters) (see Fig. 4.8). If this checkbox is checked, the value of the DIMASSOC variable is 2. If it is unchecked, the variable is set to 1.

Linear size

To create vertical and horizontal dimensions there is one command - DIMLINEAR. It measures the distance between two defining points and allows you to choose the location of the dimension line.

There are two ways to create a linear dimension: specify defining points or select an object to measure. Using the point method, you select two points in the drawing and then specify the location of the dimension line. Depending on the direction of the text, the size is vertical or horizontal. If you place a value above or below the points, AutoCAD creates a horizontal dimension, but if to the left or right, it creates a vertical dimension (Fig. 5.2).

Rice. 5.2. Dimensioning by specifying defining points

You can also create a linear dimension by selecting a line, arc, or circle. After running the DIMLINEAR command, AutoCAD will prompt:

4. Click on the lower left point of the object. You will be prompted to specify the start of the second extension line:

Specify second extension line origin:

5. Click on the right end of the bottom sloping line. A prompt will appear:

In response to this, you can determine the location of the dimension line by dragging it with the mouse.

6. Place the dimension line as shown in Fig. 5.5. AutoCAD will then complete the DIMLINEAR command.

Rice. 5.5. Horizontal dimension created by specifying definition points

7. Run the DIMLINEAR command again. A prompt will appear:

Specify first extension line origin or :

3. Press the key Enter. AutoCAD will prompt you to select an object to dimension:

Select object to dimension:

4. Select a line. The program will create defining points at its ends and issue a prompt:

Specify dimension line location or :

5. Select the Mtext option. A tab will appear on the ribbon Text Editor(Text Editor) and the default size will be highlighted. Delete this text and enter a value of 1.00.

6. Click outside the input field to close the editor. AutoCAD will display the size as 1.00.

7. Select the line you just dimensioned to activate its handles. Select the marker at one extreme point and drag it to a new location. AutoCAD changes the line length and the dimension line moves with it, but the dimension value does not update.

8. Run the DDEDIT command and highlight the size value 1.00. Remove the value 1.00 and enter<>. AutoCAD replaces the brackets with the actual line length.

9. Select the line to activate its handles and return the end point to its original position. AutoCAD changes the length of the line and the dimension line moves with it. The size value is updated to reflect the changes.

Additionally, if the actual dimension value does not match the distance between extension lines, you can add a zigzag to the linear dimension using the DIMJOGLINE command. Zigzag dimension lines are usually used when the object being measured is shown in dimensions that are smaller than actual dimensions. The application of these capabilities is shown in Fig. 5.7.

Rice. 5.7. Using Zigzag Dimensions

Creating Aligned Dimensions

Aligned dimension is another type of linear dimension. While horizontal and vertical dimensions measure distances along the axis X or Y accordingly, the aligned dimension shows the true distance between any two points. The dimension value is placed parallel to the straight line connecting the two defining points.

To create aligned dimensions, use the DIMALIGNED command. When using it, you can select two defining points or a line, arc or circle. Once you define the defining points, the Mtext, Text, and Angle options become available. Their values are identical to the corresponding parameters of the DIMLINEAR command.

Let's look at the procedure for creating aligned dimensions.

1. Open or create a drawing that contains a line, arc, or circle.

2. Run the DIMALIGNED command. A prompt will appear:

Specify first extension line origin or :

4. Place the dimensions as shown in the figure. 5.16. Press the key Esc to end the DIMCONTINUE command.

Rice. 5.16. Extended size

5. Run the DIMBASELINE command. AutoCAD will begin to extend the dimension line from the previous one and will ask you to determine the beginning of the second extension line:

Specify a second extension line origin or :

8. Select the rightmost point of the shape. AutoCAD will automatically place the base dimension above the others. Your drawing will look something like the one shown in Fig. 5.17.

Rice. 5.17. Basic size insert

Size style

We looked at how to create and place dimensions in a drawing. However, this is only part of the process. In this section, you will learn how to control the appearance of dimension objects using dimension styles.

A dimension style is a collection of parameters stored under a specific name and applied to dimensions as settings. Dimension styles control the appearance and behavior of a dimension object: the arrowhead used, the text style, allowed values and formatting, and the overall scale of the dimension.

Dimension styles function like text or layer styles: you set a specific style as current, and any new objects are created using the settings contained in that style. Dimension styles are controlled using the DIMSTYLE command.

When you run the DIMSTYLE command, a dialog box appears Dimension Style Manager(Size Style Manager) (Fig. 5.18). In this window you can create and change a dimension style.

Rice. 5.18. Size Style Manager Window

In field Styles(Styles) Displays dimension styles. Drop-down list List(List) allows you to specify which styles should be shown in the field Styles(Styles). You can choose to display all styles or only those used in the drawing.

Additionally, using the checkbox Don't list styles in Xrefs(Don't List Styles in Xref) You can select, show, or hide dimension styles contained in Xrefs.

In area Preview of(Preview) displays an example of the currently selected dimension style being used. The buttons located on the right side of the window allow you to create, change, cancel, and compare dimension styles.

Creating a Dimension Style

AutoCAD comes with a predefined default dimension style - ISO-25. It can be changed, renamed, and even deleted if it is not listed as current. Style Options ISO-25 are defined in the template file used to create the drawing.

To create a new dimension style, click the button New(New) in the dialog box Dimension Style Manager(Size Style Manager). As a result, a window will appear Create New Dimension Style(Create a new dimension style) (Fig. 5.19).

Rice. 5.19. New Dimension Style Dialog Box

When you create a new dimension style, AutoCAD makes a copy of the existing style as a starting point. In the window Create New Dimension Style(Create New Dimension Style) provides a name for the new dimension style and indicates which style you want to copy to use as a base. You can also create a style that only applies to a specific type of size. For example, you might want all text dimension values to be aligned to dimension lines, but the text values for radius and diameter dimensions to be placed horizontally. In such cases, so-called child styles are used, which appear as substyles of the main dimension style.

Note
If you select a child dimension style in the Create New Dimension Style dialog box, the Dimension Style Manager window's Preview of area displays only those dimension style options that differ from the parent. The Description area shows the differences between the parent and child styles.

Let's create a new dimension style and apply it to the drawing shown in Fig. 5.20.

Rice. 5.20. Original drawing

1. Run the DDIM command. A dialog box will appear Dimension Style Manager(Size Style Manager). Click the button New(New) to open a window Create New Dimension Style(Create a new dimension style).

2. Enter the Mech name in the field New Style Name(Name of the new style) and make sure that in the list Start With(Start with) style selected ISO-25, and in the list Use for(Use for) – value All dimensions(All sizes). Click the button Continue(Continue). A window will appear on the screen New Dimension Style(New size style).

3. Change, for example, on the tab Text(Text) switch position Text alignment(Text Alignment) on horizontal(Horizontally).

4. Click the button OK, to accept the settings change. You will see the window again Dimension Style Manager(Size Style Manager). The new dimension style appears in the field Styles(Styles).

5. Click the button Close(Close) to end the DIMSTYLE command.

6. Place linear dimensions. Your drawing should look something like the one shown in Fig. 5.21.

Rice. 5.21. Result of applying the new dimension style

Customizing an existing dimension style

To change the dimension style options, select its name in the window Dimension Style Manager(Size Style Manager) and click the button Modify(Change). A window will open Modify Dimension Style(Change Dimension Style), which contains seven tabs that provide settings for various aspects of dimensions.

Line options

Tab Lines(Lines) is designed to control dimension and extension lines (Fig. 5.22).

Rice. 5.22. Dimension Line Options

Region Dimension lines(Dimension Lines) allows you to set the color (Color), type (Linetype) and thickness (Lineweight) dimension lines, as well as the interval between them, used to create basic dimensions. Field Extend beyond ticks(Go Beyond Labels) is only available when certain types of arrowheads are specified. For example, if an architectural label is used, the parameter Extend beyond ticks(Extend beyond labels) specifies how much the dimension line will extend beyond the labels. You can also make the dimension line invisible on either side of the text value (the checkboxes are for this Dim line 1 And Dim line 2). This is useful when dimensioning cluttered areas where lines often crowd out the text dimension value.

Region Extension lines(Extension Lines) contains similar options for extension lines. You can set the color, type, and thickness of extension lines, adjust their length, and specify the gap between the extension line and the object for which you are dimensioning.

Symbol and Arrow Settings

Tab Symbols and Arrows(Symbols and Arrows) allows you to set the size and type of directional arrows used (Fig. 5.23).

Rice. 5.23. Symbol and Arrow Options

You can set different index arrows for the first and second dimension lines, as well as a separate arrow for the index lines (Leader). Region Center marks(Center Marks) is used to determine the size and type of center marks. Here you can specify how center marks will be displayed in radius and diameter dimensions, and also configure the creation of center mark lines with the DIMCENTER command.

You can break dimensions or extension lines where they intersect with geometry or other dimensions. Although this is not recommended drafting practice, sometimes such breaks are necessary, so in the area Dimension Break(Gap size) there is an opportunity to set the size of such a gap.

Options in area Arc length symbol(Arc Length Symbol) control where the arc length symbol is displayed when using the DIMARC command. In field Jog angle(Zigzag Angle) specifies the angle of the zigzag line segment used when executing the DIMJOGGED command.

Text settings

Tab Text(Text) controls the placement and appearance of text (Figure 5.24). In area Text appearance(Text Style) You can set the text style to be used. Clicking the ellipsis button causes a dialog box to appear Text Style(Text Style) in which you can create and edit text styles. In addition, on this tab you can configure the color and background of the text, as well as set the display of a frame around the text by checking the box Draw frame around text(Draw a frame around the text).

Rice. 5.24. Text Options

Options Text height(Text Height) and Fraction height scale(Fraction Height Scale) controls the height of the text. Coefficient Fraction height scale(Fraction Height Scale) applies to the text of the numerator and denominator in the fraction. For example, if the text height is set to 0.12 5, and the fraction height scale is 0.5, then the height of the numerator and denominator must be 0.0625 so that together they fit into the overall height of the fraction.

In area Text placement(Text Placement) you can specify the placement of text relative to dimension and extension lines. In the dropdown list Vertical(Vertical) You can select the position of the text value relative to the dimension line: above, below, or centered. If you select the value JIS the text size will be positioned according to the Japanese industry standard. List horizontal(Horizontal) specifies the placement of the text relative to the leader lines: you can place the text near the first or second leader lines, or extend it over any leader line. From the list View Direction(Viewing Direction) You can select the direction of the text: left to right or right to left. In field Offset from dim line(Offset from dimension line) specifies the distance between the line and the text value of the dimension.

Fit and scale options

Tab Fit(Fit) controls the behavior and scale of dimensions (Figure 5.25). Here you can specify what happens to dimensions if AutoCAD cannot place both dimension lines and a text value between extension lines.

Rice. 5.25. Fit and Dimension Scale Options

Using the settings located in the area Text placement(Text Placement), you can determine where the text will be placed if it is not in the default position.

For example, if the drawing needs to be printed to scale 1/8"=1"–0", you should scale all annotations in your drawing by a factor of 96. Since the drawing is reduced for printing, this ensures that the annotation is the correct size. Switch Scale for dimension features(Scale for Dimension Properties) controls the overall scale of dimension feature annotations.

Attention!
It is important to note that the Scale for dimension features parameter only affects the size of the dimension objects themselves (lines, text), and not the dimension values.

Use overall scale of(Use Global Scale) is a scale factor that applies to all dimension properties. For example, if the text values and directional arrows have a height of 0.125 and the overall scale value is 2, AutoCAD will display the text and directional arrows at a scale of 0.25.

Overall scale (switch position Use overall scale of(Use Full Scale) is most often used when dimensions are placed in modeling space (the drawing area) and you are displaying the drawing view in that space. If you are drawing a drawing from layout space (sheet), you can set the switch to Scale dimensions to layout(Scale dimensions for layout). In this case, AutoCAD automatically scales all dimension properties to match the scale of the layout viewport. This is useful when one drawing contains many views and graphic scales.

In area Fine tuning(Fine tuning) you can set some additional parameters for the size view. If the checkbox is checked Place text manually(Place Text Manually), an additional tooltip appears when creating dimensions, allowing you to locate the dimension text value after you have located the dimension line.

Checked checkbox Draw dim line between ext lines(Draw dimension line between extension lines) will force the dimension line to be placed between the extension lines regardless of the location of the text value.

Definition of Basic Units

Tab Options Primary Units(Basic units) are intended for formatting the text value of the size (Fig. 5.26). In area Linear dimensions(Linear dimensions) you can specify how the units of measurement will be displayed, and in the area Angular dimensions(Angle dimensions) – what the angular dimensions will look like.

Rice. 5.26. Dimension text value formatting options

Parameter Unit format(Units Format) sets the unit format for all dimension types except angular. It is usually adjusted to match the units of measurement of the design. In addition to the standard settings, you can also select units Desktop Windows that use the options located in the window language and regional standards(Fig. 5.27).

Rice. 5.27. Windows regional settings window

This window can be called up by running the command Start > Control Panel and clicking on the icon in the window that opens Language and regional standards.

Using a list Units format(Units format) in the area Angular dimensions(Angle dimensions) You can control the display of angular dimensions: Decimal Degrees(Decimal degrees), Degrees Minutes Seconds(Degrees, minutes, seconds), Gradians(Grady) or Radians(Radians).

Parameter Precision(Precision) controls the number of decimal places in the dimension text. It only affects the display of the text value, without changing the geometry of the drawing or affecting the actual measured value of the dimension.

In the dropdown list Fraction format(Fraction Format) You can select how fractions are displayed. This setting is only available when in the list Unit format(Unit Format) item selected Architectural(Architectural) or Fractional(Fractional). This option is used in combination with Fractional height scale(Fraction height scale) tab Text(Text).

If on the list Unit format(Unit Format) value selected Decimal(Decimal), then in the dropdown list Decimal separator(Decimal Separator) You can set the character used as the decimal separator.

In field Round off(Rounding) sets the rounding rule for dimensions of all types except angular. If you enter 0.25, all distances will be rounded to the nearest 0.25 unit value. If you enter 1.0, all measured distances will be rounded to the nearest whole number. The number of digits displayed after the decimal point depends on the setting Precision(Accuracy).

In field Prefix(Prefix) You can specify a prefix for the text size value. The specified text will be placed before the default value. You can enter any text in this field or use control codes to display special characters. For example, the control code %%C is responsible for displaying the diameter symbol.

In field Suffix(Suffix) You can also specify additional text, but in this case it will be placed after the default value. For example, you can enter the inch symbol (") and the program will insert it after each dimension value.

Region Measurement scale(Measurement Scale) contains options that allow you to define the scale factor for default dimension values. Parameter Scale factor(Scale factor) specifies the scale factor for linear dimension measurements. The value of any linear dimension is multiplied by this factor, and the final value is used as the default text. For example, if you set the dimension scale factor to 2, the text dimension value for a 1-inch line will appear as 2 inches. The value does not apply to angular measurements or rounding, or to positive or negative tolerances.

If the checkbox is checked Apply to layout dimensions only(Apply to Layout Dimensions Only), the scaled size value will only apply to dimensions created in layouts (view sheet space).

Settings in the area Zero suppression(Zero Suppression) controls the display of leading and trailing zeros in text dimension values. For example, when using decimal units of measurement, checking the Leading(Leading) means that a value of 0.5000 will be displayed as .5000. When checked Trailing The (final) size 12.5000 will look like 12.5.

Using fields Sub-units factor(Sub-dimensional factor) and Sub-units suffix(Sub-dimensional suffix) You can specify a sub-dimensional factor and a suffix. For example, if the unit of measurement is 1 m, you can specify a sub-size factor of 100 and a sub-size suffix of cm. In this case, when the size value is less than 1, for example 0.45, it will display 45 cm rather than 0.45 m.

Checkboxes 0 feet(0 in feet) and 0 inches(0 in inches) control the display of zeros in dimension values expressed in feet and inches. For example, if the checkbox 0 feet(0 in feet) is checked, a value of 0" 8" will display as 8". When checked 0 inches(0 in inches) value 12" 0" will display as 12".

Alternative units of measurement

Tab Alternate Units(Alternate Units) allows you to display dimensions in two different formats (Figure 5.28). A typical example is displaying dimensions in both millimeters and inches, for example 2.00. Tab Alternate Units(Alternate Units) contains options similar to those on the Primary Units(Basic units). To allow the use of alternative units, select the checkbox Display alternate units(Display alternative units).

Rice. 5.28. Alternate Unit Options

Parameter meaning Unit format(Unit Format) and Precision(Accuracy) is no different from similar settings on the tab Primary Units(Basic units). When using fractional unit formats (architectural and fractional), you can choose between composed and uncomposed fraction views.

Settings Multiplier for alt units(Multiplier for alternative units) and Round distances to(Round distances to) determine the conversion factor between primary and alternative units. For example, to convert inches to millimeters, set the multiplier to 25.4. This value does not affect the angular dimensions. Settings Round distances to(Round Distances To) allows you to apply rounded values to alternative dimensions. This rounded value is independent of the primary unit rounding value.

Options Prefix(Prefix), Suffix(Suffix) and checkboxes in the area Zero suppression(Zero Suppression) are configured in the same way as for basic units. For example, to place mm after the alternative units, enter Suffix(Suffix) corresponding meaning.

By switch Placement(Placement) you can choose where the alternate units will be displayed: after the main value (After primary value) or under it (Below primary value).

Tolerance settings

Tab Tolerances(Tolerances) is intended to control the display and values of tolerances for both basic and alternative units (Fig. 5.29). Settings Method(Method) controls the display of tolerances. Parameter Precision(Accuracy) and checkboxes in areas Zero suppression(Zero suppression) work in the same way as in tabs Primary Units(Base Units) and Alternate Units(Alternate Units) but only controls tolerance values.

Rice. 5.29. Tolerance Options

In the fields Upper value(Upper limit) and Lower value(Lower Limit) You can set the upper and lower limits of the tolerance parameter values.

Using the field Scaling for height(Scaling for Height), you can set the relative size of the tolerance text value. This is the scale factor multiplied by the text height of the main unit. For example, if you specify a value of 0.5, the tolerance text will be half the size of the base unit.

On the list Vertical position(Vertical position) select the vertical position of the main text value of the dimension in relation to the tolerance text: Bottom(Bottom) Middle(Middle) or Top(Above).

Let's look at how to change an existing dimension style.

1. Run the DIMSTYLE command to bring up the dialog box Dimension Style Manager(Size Style Manager).

2. Select the dimension style you created earlier Mech and click on the button Modify(Change). A dialog box will appear Modify Dimension Style(Change size style).

3. On the tab Symbols and Arrows(Symbols and arrows) set the parameter Arrow size(Arrow size) value 0.125.

4. On the tab Text(Text) click the ellipsis button next to the list Text style(Text style). A dialog box will appear Text Style(Text style). Click on the button New(New) and create a text style named DIM using the font romans.shx. Click the button Apply(Apply) and then Close(Close) to return to the window Modify Dimension Style(Change size style).

5. Select from the list Text style(Text style) text style DIM which you just created and set the parameter Text height(Text height) equal to 0.125.

6. Click the button OK, to save size style changes and return to the window Dimension Style Manager(Size Style Manager). Select Size Style Mech and click on the button Set Current(Set Current) to set this dimension style as the current one. Click the button Close(Close) to complete the DIMSTYLE command. The sizes associated with this style will be updated.

Any drawing in AutoCAD contains various kinds of dimensions, which are an integral part of graphic information for workers in production, construction, management and many other industries. In this chapter, we looked at the basic AutoCAD commands and interface elements used to insert and edit linear and angular dimensions.

AutoCAD provides the user with a variety of tools to create, modify, and update dimensional objects. Using dimension styles effectively and knowing how to set dimension parameters correctly is the key to your success when working in AutoCAD.

A drawing of a part is unacceptable without dimensions marked on it. The dimensions must completely determine the size of the product. There should be a sufficient number of them, but there is also no need to apply extra sizes.

Dimensions in the drawing can be linear, angular, radial. I also advise you to read the article “Linear dimensions determine the length, width, height of the product and are indicated in millimeters without indicating a unit of measurement. Angular dimensions are measured in degrees, minutes, seconds with the designation of the unit of measurement. Radial dimensions indicate the length of the radii or diameters of arcs and circles. The size consists of:

Extension lines drawn perpendicular to the segment being measured. Extension lines of angular dimensions are drawn radially, and when drawing the size of an arc - perpendicular to its chord or radially.
Dimension lines drawn parallel to a segment, the size of which is determined at a distance of at least 10 mm from the contour of the part. The ends of the dimension lines are limited by arrows, notches or dots. Extension lines extend beyond the dimensional lines by 1 - 5 mm. When drawing several parallel dimension lines, the smaller dimension is applied closer to the contour. Dimension lines of angular dimensions are arcs centered at the vertex of the corner or arc.
Dimensional numbers that indicate the size of the product.

Depending on the product and the orientation of the extension lines, dimensions can be horizontal, vertical, parallel, rotated, or ordinate. You can put down dimensions from a common base and form dimensional chains.

Dimensioning can be done using one of two methods. The first is that after entering a command with the mouse cursor, the object whose size is being measured is indicated and the position of the dimension line is specified. When using the second method, the mouse cursor indicates the starting points of extension lines and the position of the dimension line. In the latter case, it is recommended to enable object snap mode.

Options for applying dimensions or editing them are contained in the menu command Dimension, as well as in the form of buttons on the panel Dimension.

AutoCAD creates associative dimensions. Associativity means that when objects are changed by editing commands, the dimension elements are automatically updated.

The type of dimension in the drawing depends on the selected style. The default style is ISO-25, intended for mechanical engineering drawing. AutoCAD provides the ability to make changes to existing styles, as well as create your own styles. The selected dimension style determines the display of extension lines, the size and position of the text, the length and type of arrows, the basic spacing between dimension lines, etc. The process of applying dimensions is controlled by dimension variables, the values of which can be changed using the appropriate commands or in the dialog box DimensionStyleManager. Making changes to an existing style occurs in the dialog box Modyfy Dimension Style. On the corresponding tabs of this window you can change the value of dimensional variables. Open a window by pressing a button Modify in the window DimensionStyleManager.

To create a new style, click the button New in the window DimensionStyleManager in field NewStyleName enter a name for the style and press the button. Then on the window tabs Modyfy Dimension Style set size characteristics.

On the tab Line and tab SymbolsandArrows the color, thickness and other characteristics of dimension and extension lines are set. The type and size of the arrows is selected. On the same tab, you can choose to display or not display markers in the center of the circle, as well as their size.

On the tab Text Dimension text parameters are selected: color, style, alignment.

On the tab Fit the relative placement of dimension, extension lines and text, as well as the scale of dimensions, is controlled.

On tabs Primary Units And Alternate Units The format of units of measurement is determined, and the accuracy is set.

On the tab Tolerance The format and accuracy of the tolerances are determined.

Applying linear dimensions

Linear dimensions can be horizontal, vertical, ordinate, form stable chains, or can be applied from a common base. DIMLINEAR (DLI) Command Command entry methods:

Enter the command in one of the following ways. The system will issue a request: Specify first extension line origin or

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