Datum Identifier Symbols

A datum identifier symbol identifies a feature for a feature control frame symbol. In addition to the datum identifier (1 in the illustration), AutoCAD Mechanical supports datum notes (2 in the illustration) and thread notes (3 in the illustration) for standards that permit them. A datum note typically contains a series of datum targets, separated by commas (", "). Thread notes are typically placed on symbols attached to screw threads or gears. They specify which diameter to use as the datum. For example, in the above illustration, the thread note specifies that the pitch diameter is the datum.

NoteNot all standards allow thread notes and datum notes. Refer the table in the section Supported drafting standards for details.

Orthogonal Leaders

When you attach the symbol leader to an object, AutoCAD Mechanical forces the first segment to be perpendicular to the attached object. The subsequent leader segment is forced to be horizontal or vertical.

Surface Extension Lines

If you move the start point of the leader beyond the end of a line or arc AutoCAD Mechanical automatically draws extension lines. The default values for overshoot length and offset from end of leader is determined by the DIMEXE and DIMEXO system variables, respectively. AutoCAD Mechanical does not create extension lines for splines.

Surface Indication Lines

AutoCAD Mechanical provides command line options to create surface indication leader. This enables symbol leaders to point to a surface rather than an edge. Using surface indication leaders you can indicate the datum using a top view rather than a side view. When the datum is on the far side of a component, you can specify options so that the surface indication linetype changes to a dashed style.

NoteNot all standards allow surface indication leaders. Refer the table in the section Supported drafting standards for details.

Attach to Dimensions

Though not supported directly, you can attach Datum Identifier symbol to an object and place the start point on a dimension as shown in the preceding image. When you place the start point of the symbol on the dimension, the arrows of the dimension and leader overlap. You achieve the appearance shown in the image by changing the arrowhead of the dimension to “none”.

NoteIf you modify the distance between dimension line and the attached object, the symbol does not align to the dimension line automatically.
Supported Drafting Standards
Standard/Revision Orthogonal Leaders Surface Extension Lines Surface Indication Lines Datum Notes Thread Notes
ANSI ASME Y14.5 M -1994 Yes Yes      
ASME Y14.5M - 1982 Yes Yes      
BS 308 Part 3 -1990 Yes Yes      
CSN 01 3138 -1994 Yes Yes      
DIN ISO 1101:2008 DIN EN ISO 5459:2008 Yes Yes Yes Yes Yes
DIN ISO 1101:1983 DIN EN ISO 5459:1982 Yes Yes      
GB/T 1182 -2008 Yes Yes Yes    
GB/T 1182 -1996 Yes Yes Yes   Yes
GOST 2.308-79 Yes Yes      
ISO 1101:2004 ISO 5459:1981 Yes Yes Yes Yes Yes
ISO 1101:1983 ISO 5459:1981 Yes Yes      
JIS B 0021 (1998) Yes Yes Yes    
JIS B 0021:1984 JIS B 0022:1984 Yes Yes     Yes

Procedures
To create a datum identifier symbol

  1. Click Annotate tab Symbol panel Datum Identifier. At the Command prompt, enter AMDATUMID.
  2. In the drawing area, select an object to attach the datum identifier to.
  3. If the attached object is a line:
    • Specify the start point for the leader.
  4. Specify the next point (vertex) on the leader.
  5. Press ENTER to end the selection.
    NoteAutoCAD Mechanical forces the first leader segment to be perpendicular to the attached object and the next segment to be horizontal or vertical. To override this restriction, press the Toggle Symbol Leader Orthogonal Mode key (SHIFT + F, by default) as you drag the crosshairs.
  6. In the Datum Identifier dialog box, enter the identifying letters.
  7. Click OK.
To create a datum identifier symbol with a surface indication line

  1. Click Annotate tab Symbol panel Datum Identifier. At the Command prompt, enter AMDATUMID.
  2. Select an object to attach the datum identifier to.
  3. At the command prompt, enter F.
    NoteThe surFace option is available only if the revision of the standard in use permits surface indication lines
  4. Specify the start point of the surface indication line. (1 in the illustration above).
  5. Specify one or more points to define the vertices of the leader (2,3 and 4 in the illustration above), and then press ENTER.
  6. In the Datum Identifier dialog box, enter the data.
  7. Click OK.
To attach a datum identifier symbol to a dimension

  1. Click Annotate tab Symbol panel Datum Identifier. At the Command prompt, enter AMDATUMID.
  2. In the drawing area, select the extension line of the dimension to attach to.
  3. Specify the end of the dimension line as the start point of the leader.
  4. Specify a point to define a vertex, if required.
  5. Press ENTER.
  6. In the Datum Identifier dialog box, enter the identifying letters.
  7. Click OK.
TipTo create the datum identifier symbol without leader, specify only the start point and press ENTER.
To change the arrowhead of a symbol
  1. In the drawing area, double-click the symbol to edit.
  2. From the Arrowhead drop-down list, select an arrowhead.
  3. Click OK.
To attach a symbol to an object
  1. In the drawing area, double-click the symbol to edit.
  2. Click Attach. The dialog box hides.
    NoteThe Attach button is available only if the symbol is not attached to an object.
  3. Select an object in the drawing to attach the symbol to. The dialog box is displayed again.
  4. Click OK.
To detach a symbol from an object
  1. In the drawing area, double-click the symbol to edit.
  2. Click Detach.
    NoteThe Detach button is available only if the symbol is attached to an object.
  3. Click OK.
To edit a feature control frame symbol

  1. In the drawing area, double-click the feature control frame symbol to edit.
  2. In the Feature Control Frame dialog box, perform the changes.
  3. Click OK.
To change the Toggle Symbol Leader Orthogonal Mode key
  1. Click Manage tab Customization panel User Interface. At the Command prompt, enter CUI.
  2. In the Customize tab, in the tree view, expand AMPP Keyboard Shortcuts Temporary Override Keys.
  3. In the expanded branch, select Toggle Symbol Leader Orthogonal Mode.
  4. In the Properties pane, select the Key(s) row.
  5. Click the button displayed at the right corner of the Key(s) row.
  6. Press the new shortcut key.
  7. Click OK until all dialog boxes close.
Commands
AMDATUMID

Creates a datum identification symbol and attaches it to an object in the drawing area.

 Ribbon: Home tab Annotate panel Symbol drop-down Datum Identifier. Not available on the ribbon in the current workspace.
 Toolbar: Symbols
 Menu: Annotate Symbols Datum IdentifierDoes not exist in the menu in the current workspace.
 Command entry: amdatumid

You can specify up to 2 characters to identify datum features and also select the type of datum feature triangle to use at the end of the leader line.

COMMAND LINE OPTIONS

Select object to attach: Select an object in the drawing to attach the symbol. To it to anything, click the position you want to place the arrowhead of the leader. If you want to place the symbol without a leader, click the position you want to place the symbol

Object to attach

Attaches the symbol to an object. Subsequent prompts differ depending on the type of object you attach to

Line selected

Attaches the symbol to a line and allows you to move the crosshairs along the line so that you can specify a start point for the leader.

 

Specify start point or [surFace]: Specify the start point of the leader or enter F to point to a surface instead of an edge.

NoteDrafting standards that do not support surface indication leaders do not prompt you for the surFace option.
     
 

Start point

Specifies the position of the leader arrow.

 

Specify next point or [Symbol/startPoint] <Symbol>: Specify the next vertex of the leader or press ENTER to place the symbol. Enter P to return to the previous prompt and respecify the start point.

NoteAutoCAD Mechanical forces the first leader segment to be perpendicular to the attached line. To override this restriction, press the Toggle Symbol Leader Orthogonal Mode key (SHIFT + F, by default) as you drag the crosshairs.
 

Specify next point or <Symbol>: Specify the next vertex of the leader or press ENTER to place the symbol.

NoteAutoCAD Mechanical forces these leader segments to be horizontal or vertical. To override this restriction, press the Toggle Symbol Leader Orthogonal Mode key (SHIFT + F, by default) as you drag the crosshairs.
     
 

Surface

Adds an additional arrowhead, leader and reference line to the symbol, to enable you to point to a surface rather than an edge.

 

Specify start point or [Edge]: Specify the start point of the surface indication leader (1 in the illustration above) or press E to return to the previous prompt.

     
   

Start point

Specifies the arrowhead position of the surface indication leader (1 in the illustration above).

   

Specify next point or <startPoint>: Specify the vertex of the surface indication leader (2 in the illustration above) or press P to return to the previous prompt.

   

Specify next point: Specify the next leader vertex (3 in the illustration above). The datum feature triangle is placed at a fixed distance from the first vertex (2 in the illustration above).

NoteAutoCAD Mechanical forces these leader segments to be horizontal or vertical. To override this restriction, press the Toggle Symbol Leader Orthogonal Mode key (SHIFT + F, by default) as you drag the crosshairs.
   

Specify next point or <Symbol>: Specify the next vertex of the leader (4 in the illustration above) or press ENTER to place the symbol.

     

Arc, circle, ellipse or spline selected

Attaches the symbol to the selected object and allows you to specify the next point for the leader. The start point is automatically determined based on the selected point and the first leader segment being perpendicular to the attached object.

 

Specify next point or [surFace/Symbol/startPoint] <Symbol>: Specify the next vertex of the leader. Enter F to point to a surface instead of an edge. Enter P to fix the start point. Press ENTER to place the symbol without a leader.

NoteAutoCAD Mechanical forces the first leader segment to be perpendicular to the attached line. To override this restriction, press the Toggle Symbol Leader Orthogonal Mode key (SHIFT + F, by default) as you drag the crosshairs.
NoteDrafting standards that do not support surface indication leaders do not prompt you for the surFace option.
     
 

Surface

Adds an additional arrowhead, leader and reference line to the symbol, to enable you to point to a surface rather than an edge.

 

Specify start point or [Edge]: Specify the start point of the surface indication leader (1 in the illustration above) or press E to return to the previous prompt.

     
   

Start point

Specifies the arrowhead position of the surface indication leader (1 in the illustration above).

   

Specify next point or <startPoint>: Specify the vertex of the surface indication leader (2 in the illustration above) or press P to return to the previous prompt.

   

Specify next point: Specify the next leader vertex (3 in the illustration above). The datum feature triangle is placed at a fixed distance from the first vertex (2 in the illustration above).

NoteAutoCAD Mechanical forces these leader segments to be horizontal or vertical. To override this restriction, press the Toggle Symbol Leader Orthogonal Mode key (SHIFT + F, by default) as you drag the crosshairs.
   

Specify next point or <Symbol>: Specify the next vertex of the leader ((3 in the illustration above) or press ENTER to place the symbol.

     
   

Next point

Specifies the location of the next vertex of the leader.

   

Specify next point or <Symbol>: Specify the next vertex of the leader or press ENTER to place the symbol.

NoteAutoCAD Mechanical forces these leader segments to be horizontal or vertical.
     
   

Symbol

Places the symbol at the last clicked point.

     
   

Start point

Specifies the position of the leader arrow.

Place the symbol without attaching

Places the start point of the leader at the positioned you clicked, and does not attach the symbol to anything.

Specify next point or <Symbol>: Specify the next vertex of the leader or press ENTER to place the symbol.

NoteAutoCAD Mechanical forces all leader segments excluding the first, to be horizontal or vertical. .

Specify next point or [surFace/Symbol] <Symbol>: Specify the next vertex of the leader or enter F to point to a surface. Press ENTER to place the symbol in the drawing area without a leader.

NoteDrafting standards that do not support surface indication leaders do not prompt you for the surFace option.
     
 

Surface

Adds an additional arrowhead, leader and reference line to the symbol, to enable you to point to a surface rather than an edge.

 

Specify start point or [Edge]: Specify the start point of the surface indication leader (1 in the illustration above) or press E to return to the previous prompt.

     
   

Start point

Specifies the arrowhead position of the surface indication leader (1 in the illustration above).

   

Specify next point or <startPoint>: Specify the vertex of the surface indication leader (2 in the illustration above) or press P to return to the previous prompt.

   

Specify next point: Specify the next leader vertex (3 in the illustration above). The datum feature triangle is placed at a fixed distance from the first vertex (2 in the illustration above).

NoteAutoCAD Mechanical forces these leader segments to be horizontal or vertical. To override this restriction, press the Toggle Symbol Leader Orthogonal Mode key (SHIFT + F, by default) as you drag the crosshairs.
   

Specify next point or <Symbol>: Specify the next vertex of the leader or press ENTER to place the symbol.

     
 

Symbol

Places the symbol at the last clicked point.

Datum Identifier dialog box

Symbol tab

 

Options

   

Datum on far side

Changes the line type of surface indication leaders to indicate that the datum is on the far side of a component. The icon to the left of the check box changes to indicate the current state.

NoteThis option is visible only in the revisions of drafting standards that permit surface indication lines.
 

Requirements

Contains buttons and edit boxes to specify the datum. The edit boxes are named only in tooltips. Move the pointer over them to identify them.

   

Insert symbol

Displays a palette enabling you to insert a special character at the current cursor position in the Datum Note or Thread Note boxes. The preview in the drawing area shows the special character while the dialog box shows the corresponding control key sequence.

NoteThis option is visible only in the revisions of drafting standards that permit datum notes or thread notes.
   

Datum identifier

Specifies a label for the datum identifier (1 in the image above). You can specify a maximum of two characters for the label.

   

Datum note

Specifies reference datum targets that correspond to one or more points on a surface. Typically this box contains a series of datum targets separated by commas (2 in the image above).

NoteThis option is visible only in the revisions of drafting standards that permit datum notes.
   

Thread note

Specifies which diameter of a screw or gear to use as the datum (3 in the image above).

NoteThis option is visible only in the revisions of drafting standards that permit thread notes.

Leader and Text tab

 

Leader

   

Arrowhead

Specifies the type of datum feature triangle to use at the end of the leader line. Select an arrowhead from the drop-down menu. The list of arrowheads conforms to the current drafting standard. The default arrowhead is the standard arrowhead for symbols. Set it in the Options dialog box.

   

Surface arrowhead

Specifies the type of arrowhead to use at the end of the surface indication leader line. When the arrowhead is set to By Standard, it acquires the arrowhead from the current drafting standard. Thereafter, if you change the arrowhead selected for the current drafting standard (in the Datum and Feature Identifier Settings dialog box), the arrowhead for this symbol updates automatically.

NoteThis option is available only if a surface indication line exists for the symbol you are editing.
    Edit object attachment
     

Attach

Attaches the symbol to a geometry in the drawing.

     

Detach

Detaches the symbol. The symbol becomes a free-standing object.

   

Surface extension line

Controls options for extension lines to the start point of the leader. Extension lines are drawn only if you move the start point of the leader beyond the end of the line or arc it is attached to. The options in this section are available only if extension lines for this symbol exist.

     

Offset from object

Defines the distance between the surface extension line’s start point and the attached object’s end point.

     

Sync

Loads values for the offset from the DIMEXO system variable.

     

Extension beyond leader

Defines the distance between the surface extension line’s end point and the leader start point.

     

Sync

Loads values for the extension from the DIMEXE system variable.

   

Settings

Opens the Datum and Feature Identifier Settings dialog box and enables you to edit the default settings for the current drafting standard.

Datum and Feature Identifier Settings dialog box

Use the Datum and Feature Identifier Settings dialog box to specify the defaults settings of datum and feature identification symbols, for the current drafting standard.

Revision

Displays most recent revision of the standard this symbol complies with.

Leader

 

Arrowhead

Specifies the type of the leader arrowhead. When the arrowhead is set to ByNameOfCurrentDraftingStandard, it acquires the arrowhead from the master settings of the current drafting standard. If the master setting changes, the arrowheads for all datum and feature identifier symbols that are set to ByNameOfCurrentDraftingStandard, change automatically.

 

Size

Specifies the size of the leader arrowhead. When the arrow size is set to ByNameOfCurrentDraftingStandard, it acquires the arrow size from the master settings of the current drafting standard. If the master setting changes, the arrow size for all datum and feature identifier symbols based on the current drafting standard change automatically.

 

Surface arrowhead

Specifies the arrowhead to use for surface indication leaders.

NoteThis option is visble only for the standards that permit surface indication leaders.
 

Size

Specifies the size of the surface indication leader arrowhead.

NoteThis option is visble only for the standards that permit surface indication leaders.
 

Far side linetype

Specifies the linetype to use for surface indication lines that point to hidden surfaces.

NoteThis option is visble only for the standards that permit surface indication leaders.
 

Color

Specifies the color of the leader. When the leader color is set to ByNameOfCurrentDraftingStandard, it acquires the color from the master settings of the current drafting standard. If the master setting changes, the leader color of all datum and feature identifier symbols based on the current drafting standard change automatically.

Text

 

Height

Specifies the text height for symbol text. When the height is set to ByNameOfCurrentDraftingStandard, it acquires the text height from the master settings of the current drafting standard. If the master setting changes, the text height of all datum and feature identifier symbols based on the current drafting standard change automatically.

If the current standard is a custom standard, you can specify a non-standard text height. If not, the AutoCAD Mechanical restricts you to selecting a value from the list.

 

Color

Specifies the color of symbol text. When the text color is set to ByNameOfCurrentDraftingStandard, it acquires the color from the master settings of the current drafting standard. If the master setting changes, the text color of all datum and feature identifier symbols based on the current drafting standard change automatically.

NoteIf the text height changes, the color automatically changes to the default color corresponding to that text height. Text object colors are set from the Object Property Settings dialog box.

Restore Defaults

Returns all values to the default values for the current standard.