DIM command improved

DIM command improved


Dimensioning is potentially one of the most complicated tasks that you are likely to perform in Autocad. Autocad provides something like sixty-five different variables (settings) to define each dimension style and unless rigid rules are adhered to it is unlikely that any two drafters will produce dimensions that look alike. In addition to using pre-defined styles it is also possible to override those styles for one or more dimension occurrences.


Whether they are diligently adhered to or not most offices set their own preferred drawing styles and this includes dimensions. Architects in particular have their own preferred style and fortunately this is fairly consistent throughout the profession; a benefit bestowed by the now somewhat defunct SAA drafting code.


MYCADKEYS helps to maintain standards by automatically pre-defining a standard range of dimension styles when a new drawing is created and also automatically sets the correct text size and dimension scale when a plot scale is entered.


MYCADKEYS’ automatic dim-style management facility is activated by MYCADKEYS “D” command. If dimension assistance is not required; then the generic Autocad command "`D" may be used.


Pre-defined dimension styles include: Architectural, Engineering, Coordinating, Grid and Running dimensions. DIM Style definitions and text fonts may be altered by editing #D.LSP and #MYCADKEYS-TEXT-STYLES.LSP. The default font is SWIS721 LtCn BT.TTF


MYCADKEYS was originally written for professional Architects and does not attempt to answer every dimensioning situation for every profession. You may, however, easily edit the default styles to suit your own requirements.

Dimension layer:

You may optionally allow MYCADKEYS to set the dimension layer for you or turn off the automatic layer feature and manually set the dimension layer yourself. Whatever you choose it is recommended that dimensions be given their own specific layer name.


If you are using MYCADLAYERS it is useful to use the character D in the MYCADLAYERS Line-type field. Dimension layers may also optionally be linked to the object to which they refer by using the MYCADLAYERS Object code. .

Size of dimension features:

When dimensioning in model-space (the recommended option for building dimensions) the size of the dimension features (text size, arrow size etc.) must be set to suit the proposed plot scale. For example text that is required to be 3mm high in a 1:100 drawing on the plotted sheet must be 300mm on the drawing in model-space. To avoid having to calculate correct text sizes for every combination of scale and plotted text size MYCADKEYS does this automatically. MYCADKEYS creates and maintains its own system-variable “plot-scale” from which both text and dimension sizes are generated. Plot-scale will default to the existing system-variable Dimscale and if changed will automatically update the Dimscale to match.


(MYCADKEYS'  T command also refers to the plot-scale setting to determine the appropriate text size for the drawing scale).


MYCADKEYS assumes that text styles, and thus dimension text sizes, are defined with zero height. This allows full flexibility in adjusting the size of dimension text as well as ordinary text without having to define a new text style for every variation in text size.


MYCADKEYS uses Autocad’s dimension variables such as dimtxt, dimtsz” and “dimasz” to control the size of individual dimension features and uses the master-variable “dimscale” to scale the result of the individual variables. A dimasz of 2 and dimscale of 1 produces arrowheads 2 units long. Changing the dimscale to 100 will produce arrowheads 200 units long and scale up all other dimension features as well. Thus MYCADKEYS can quickly adapt to different plot scales simply by adjustment the MYCADKEYS variable “plot-scale” that in turn automatically adjusts Dimscale to match.


MYCADKEYS' dimensioning command requires a Plot-scale to be set. This automatically sets the Autocad dimscale to the MYCADKEYS Plot-scale; thus determining the size of dimension features. MYCADKEY' Text command also uses the variable dimscale (Plot-scale) to determine the current text size. Changing the plot-scale in the D command automatically changes the plot-scale in the Text command and vice versa.

Dimension text style:

Many drawing offices require the use of standard text fonts. A common choice is ARIAL but a preferred alternative is SWIS721 LtCn BT. (close in style to traditional template styles and also lighter and neater on drawings). MYCADKEYS' Text and Dimension commands use SWIS721 LtCn BT to generate a style called SWISLTCNBT. This style is generated automatically, when a new drawing is started.


TEXTSTYLE and DIMTXSTY can be reassigned to any one of approx nine pre-defined styles in the file JINNI-TEXT-STYLES.LSP.

Text Colour:

MYCADKEYS assumes that users will prefer to subdue the screen appearance of dimensions in comparison with the drawing objects to which they refer. Dimensions are therefore, by default, coloured light grey (colour 8). Users may nominate their own preferred default colour for dimensions, but should first study the full pen-colour/line-thickness recommendations offered by MYCADKEYS. To change pen/colour settings edit the file JINNI-PEN-COLORS.LSP.

Interpretation of prompts:

Bold text in the command prompts below is for emphasis within this document only – it will not appear in Autocad.

Main prompt:

For generic Autocad command use Command: `D

Object-code= ON / Plot= 1:100 / Rotn= 45 / $tyle= ARCH,ctrl,engr,grid / lYr= layername

<<dimension offset-point / Rotation-or-typit <[settings]>:


Line one advises that if you need to use generic Autocad Dim command use

Command: `D <enter>

Line two displays the current dimension settings.

Line three is the active prompt i.e. select the dimension offset-point for the first line of dimensions or press <enter> or [spacebar] to activate settings options.

Dimension settings prompt:

Object-code= ON / Plot= 1:100 / Rotn= 45 / $tyle= ARCH,ctrl,engr,grid / lYr= layername

Press option key-letter / <[done]>


Line one displays current settings.

Line two is the active prompt i.e. pressing a key-letter activates one of the relevant options below. As settings are changed the above prompt repeats but with the new values substituted or highlighted. When done press [spacebar] or <enter> to return to the main prompt.



Indicates ON or OFF. If ON, MYCADKEYS will prompt for an object code and adjust the layer name of the new dimension accordingly.



Indicates current intended plot-scale of the drawing. Pressing P then entering a number changes the variable dimscale and hence adapts the size of dimensions to suit the current plot-scale.



A number indicates the current rotation of the dimension lines. Press R to show the angle by picking points or begin entering a number. The rotation angle is used for subsequent dimensions until reset to zero.



Several styles are shown e.g: / $tyle= ARCH, ctrl. eng, grid / The current setting is in uppercase. Repeatedly pressing $ toggles between them.



Indicates the destination layer for new dimensions. Pressing L will start the MYCADKEYS get-layer name function allowing the user to control dimension layers. This feature may be turned off by those who prefer to set layers themselves.



Returns to main prompt.


Main prompt – active options:

<<dimension offset-point / Rotn-or-typit /<[settings]>:


Identify a point from which to offset the first line of dimensions, change rotation or press [spacebar] or <enter> to change settings.

After an offset point is identified the following prompt appears

Side to offset dimension set: NON:

Identify a point.


First dimension point: <<point / OSNAP / <[done]>: NON:

Pick a point with the left mouse button or press an OSNAP key to set a temporary osnap.


Next dimension point / OSNAP / <[done]> (repeats after each point)

Identify subsequent points or indicate <[done]>.


First dimension point of next line: <<point / OSNAP / <[done]>: NON:


Next line of dimensions:

Repeats same order of prompts as “First line of dimensions:” except for “Side to offset dimensions:” Subsequent lines of dimensions are offset from the previous by a distance calculated from dimscale and other relevant dimstyle settings.


<[done]> takes user to Next line of dimensions;


Repeatedly selecting <[done]> backs up through the command one step at a time until the command is terminated. Escape will also terminate the command at any time.


<[done]> takes user back to First line of dimensions:

<[done]> takes user back to main prompt;

<[done]> exits command.


Other dimension functions:

MYCADKEYS provides shortcut functions equivalent to most other Autocad dimension functions plus a few extra useful ones:


DE Dimension Edit

DEA Annotate

DEF Fix rotation of text

DEF2 Fix rotation of text - option 2

DEH Hometext

DEN Newtext

DEU Update

DL Leader

DO Object code ON/OFF


D% Set dimScale

DL Layer

D? random information

D$O dim$tyle OVERRIDE



MYCADKEYSI Command: DA provides a simple dimension annotation tool that adds a text note in a matching style, layer, size and rotation below the selected dimension’s text.



Displays and allows initiation of all edit options.



Sometimes when a drawing and its dimensions are rotated the dimension text displays in the wrong orientation. DF or DF2 will often correct the display.



Restores original position of the text that has been moved.



Allows editing of dimension text. Entering “<>” will restore original dimension value.


Object code ON/OFF:

Toggles object-code facility ON and OFF.


Starts standard Autocad DIMRADIUS command.



Changes system variable dimscale.



Updates selected dimensions.



Corrects dimension layers after explosion. – Not yet implemented.



Useful information.


Dim$tyle OVERRIDE:

Starts standard Autocad DIMOVERRIDE command. MYCADKEYS recommends that DIMOVERRIDE be used only in exceptional circumstances.