Dimensioning

This section covers the enhanced datum dimensioning available in SI Mechanical. Datum or ordinate dimensioning is typically used for dimensioning flat parts such as sheet metal with holes and cutouts. It can also be used to dimension crowded drawings where standard dimensioning would not easily fit.

XYDIM Command

The XYDIM (X Y DIMension) command is an enhanced variation of AutoCAD's ordinate dimensioning having the advantage of allowing multiple angled dimension offsets. The prompt sequence is the same whether you are dimensioning an X or a Y coordinate.

Command: xydim
Exit/Xdim/Ydim/Zero/<default>: x
Indicate X dimension location: Pick point.
Dimension to: Pick point.
Dimension text <default>: [Enter]
Start of offset: Pick point.
End of offset: Pick point.
Start of offset: [Enter]

To end the offset sequence, press [Enter].

Note: If the DIMASO AutoCAD system variable is set to 1, you can only have one offset. You can use multiple offsets when using non-associative dimensioning.

To indicate a dimension location, either pick a position or, if a default is shown, you accept it, by entering a [Enter] or a [Space], to align the dimension with the previous one. When selecting a dimension location remember:

  • An X dimension requires a vertical location.
  • A Y dimension requires a horizontal location.

    The Zero option lets you reset the UCS origin to a new zero point location.

    Command: xydim
    Exit/Xdim/Ydim/Zero/<default>: z
    Indicate zero point: Pick point.

    XYDIM locations

    AXYDIM Command

    The AXYDIM (Automatic X Y DIMension) command runs XYDIM in an automatic mode, and allows you to dimension a drawing by picking items to dimension as a group. AXYDIM then decides how to place the dimensions in the drawing and does it for you.

    Command: axydim
    Indicate Zero point <options>:
    Select objects: Do so.
    Indicate X dimension location: Pick point.
    Indicate Y dimension location: Pick point.

    If you press [Enter] instead of indicating a zero point, a dialogue box will be displayed allowing you to specify certain types of entities and dimension options before starting the automatic dimensioning.

    AXYDIM dialogue box

    Type
    This group of buttons set the type of dimensions that AXYDIM will draw.
    Space factor:
    This edit box sets the relative spacing between dimensions. A value of 0.5 would leave at least half the dimension text height between each dimension.
    Min apex angle:
    This edit box sets the minimum apex angle to use when dimensioning to arc apexes. If you have angled sides with fillets on the corners, the corners will be dimensioned as long as they meet the minimum apex angle setting.
    Block nest level
    This group sets how deep to go into blocks to obtain entities to dimension. If the item is a block, and you want the items inside the block to be dimensioned, set it to 1. When the items inside the block are nested blocks, you must set the number higher to dimension items inside the nested blocks. The higher the setting the deeper it will go into the nested blocks.
    Lines
    This check box sets AXYDIM to dimension to line endpoints.
    Circles
    This check box sets AXYDIM to dimension to circle center points.
    Add center marks
    This check box sets AXYDIM to add center marks to each circle that it dimensions to.
    Blocks inserts
    This check box sets AXYDIM to dimension to block insert points.
    Arc apexes
    This check box sets AXYDIM to dimension to the intersection of the two tangencies of arc endpoints.
    Text inserts
    This check box sets AXYDIM to dimension to text insert points.
    X coordinates
    This check box sets AXYDIM to draw X coordinate dimensions.
    Y coordinates
    This check box sets AXYDIM to draw Y coordinate dimensions.

    XYTABLE Command

    The XYTABLE (X Y TABLE) command draws a table of sizes and X and Y coordinates of selected circles and hole items in a drawing. The circles and holes are grouped in the chart by size, X coordinate, and Y coordinate, in ascending order. Circle sizes are included inside the chart while hole descriptions are placed just below the chart. The hole descriptions are identical to those produced by the LABEL command.

    Command: xytable
    Indicate zero point <options>:
    Select objects: Do So.
    Upper left corner of table: Pick point.

    If you press [Enter] instead of indicating a zero point, a dialogue box will be displayed allowing you to control center marks and hole symbol markers.

    XYTABLE dialogue box

    Hole symbols are used to label each circle. It is an alphanumeric string that is generated in ascending order of circle size.
    On center
    This button places the hole symbols at the circle center point
    Angled
    This button places the hole symbol just outside the circle radius at the specified angle from the center.
    None
    This button indicates that no hole symbols will be drawn.
    Symbol angle:
    This edit box sets the angle for hole symbols. The value indicates the angle of an imaginary line between the circle center and the hole symbol.
    Add center marks
    This check box sets XYTABLE to draw center marks on all circles.

    All valid entities in the selection set will be processed and a table will be drawn.

    XYTABLE example

    See the following DPVAR variables that directly affect the XYDIM, AXYDIM, and XYTABLE commands:

    XYMINUS