Part 2 - A few useful AutoCAD Drawing variables

In my last article, I discussed a number of variables that take effect over the AutoCAD application itself, this time I’m going to cover a few of the common Drawing specific variables – i.e. those settings that apply to the individual dwg files rather than globally. I’ve covered a couple of the important ones previously, so also be sure to check out the previous posts on INSUNITS and VISRETAIN.

There are numerous variables available to control all manner of settings within the AutoCAD drawing environment, those shown below are just a few examples that may be encountered during a typical charting project. Further details can be found in the AutoCAD Help documentation.

FRAME – The Frame variable turns the display of frames on and off for all external references, images, and DWF, DWFx, PDF and DGN underlays. When you insert an Image, an underlay or perform an XCLIP around an external reference, the border around that object can optionally be displayed. The Frame setting overrides the individual IMAGEFRAME, DWFFRAME, PDFFRAME, DGNFRAME and XCLIPFRAME settings and can have the following values:

0 - The frame is not visible and it is not plotted

1 - Displays the frame and allows it to be plotted

2 - Displays the frame but keeps it from being plotted

3 - The individual setting varies for all underlays in the current drawing

(i.e. external references, images, and DWF, DWFx, PDF underlays all have different frame settings).

Note this value is used internally by AutoCAD, so the FRAME variable cannot be set to 3 by the User.

IMAGEFRAME, XCLIPFRAME, DWFFRAME, PDFFRAME and DGNFRAME can be set individually to a value of 0, 1 or 2 following the same conventions as per the FRAME variable above.

LWDISPLAY – Controls whether the lineweights of objects are displayed and can be set to either ON or OFF. Note that the setting is controlled separately for model space and all paper space layouts.

LAYEREVAL – Specifies whether the layer list is evaluated for new layers when added to the drawing or to the attached xrefs. Setting LAYEREVAL to 0 turns it off, 1 detects when new xref layers have been added in the drawing and 2 detects when new layers have been added in the drawing and xrefs.

LAYERNOTIFY – Specifies when an alert displays when unreconciled new layers are found and can be set to a bitcode value consisting of the following:

0   - Off
1   - Plot
2   - Open
4   - Load/Reload/Attach for xrefs
8   - Restore layer state
16 - Save
32 - Insert

Note: LAYEREVALCTL overrides the LAYEREVAL and LAYERNOTIFY setvars. When LAYEREVALCTL = 0 it acts like a global off (but not a global on). There is no effect even if LAYEREVALCTL is turned on if LAYERNOTIFY = 0 or LAYEREVAL = 0. LAYEREVALCTL must be set to 1 for LAYERNOTIFY and LAYEREVAL to function correctly.

As explained in the previous article,you can display a Dialog box showing the numerous AutoCAD variables available and their current settings using the System Variable Editor Express Tool.