Understanding DWG Files and Fixing Them

The native AutoCAD file for saving drawings is ".DWG" (short form extension for "drawing"). The DWG file can be likened to a moveable database, storing tables of information such as geometry, views, layers, configurations, third-party extensions and links to other data sets like XREF or BLOCK. The first .DWG binary format "MC0.0" was implemented in 1982 with the AutoCAD 1.0 release. A user can check any DWG file directly by opening in a binary-text editor (I use vi/vim) and checking the first six characters like we did here:

That's it. Those six characters "hard-code" the rest of the drawings data as to which version protocol it obeys. in this case the file is DWG 2010 format. How do we know? Because AC1024 is code for 2010 DWG. Many of you have probably seen this table somewhere before:

DWG Version	"Internal" Version	Release Date	AutoCAD version(s)
DWG R1.0	MC0.0	April 1983	AutoCAD Release 1.0
DWG R1.2	AC1.2	August  1983	AutoCAD Release 1.2
DWG R1.40	AC1.40	October 1983	AutoCAD Release 1.40
DWG R2.05	AC1.50	October 1984	AutoCAD Release 2.05
DWG R2.10	AC2.10	May 1985	AutoCAD Release 2.10
DWG R2.21	AC2.21	June 1986	AutoCAD Release 2.21
DWG R2.22	AC1001, AC2.22		AutoCAD Release 2.22
DWG R2.50	AC1002	June 1986	AutoCAD Release 2.50
DWG R2.60	AC1003	April 1987	AutoCAD Release 2.60
DWG R9	AC1004	September 1987	AutoCAD Release 9
DWG R10	AC1006	October 1988	AutoCAD Release 10
DWG R11/12	AC1009	October 1990	AutoCAD Release 11 & 12
DWG R13	AC1012	November 1994	AutoCAD Release 13
DWG R14	AC1014	May 1997	AutoCAD Release 14
DWG 2000	AC1015	March 1999	AutoCAD 2000 - AutoCAD 2002
DWG 2004	AC1018	March 2003	AutoCAD 2004 - AutoCAD 2006
DWG 2007	AC1021	March 2006	AutoCAD 2007 - AutoCAD 2009
DWG 2010	AC1024	March 2009	AutoCAD 2010 - AutoCAD 2012
DWG 2013	AC1027	March 2012	AutoCAD 2013 - AutoCAD 2017

AutoCAD configurations can be divided into two groups: global software "Options" and drawing-specific "Settings". The Autodesk DWG files spec includes numerous configuration settings that get stored into the individual DWG file. One way of implementing certain drawing settings across all new drawings is to save those settings into the Drawing Template FIle (".DWT"). With progeCAD 2017, the default .DWT folder is:
%APPDATA%\PSOFT\progeCAD x64\R17\Professional - English\Templates
But the path can be configured in Options -> "Path/Files" tab -> Templates

DWG like many high-precision CAD formats can accumulate erros over time. These errors can originate from geometry, block handling, API errors and many other sources. DWG errors can result in degraded (slow/"glitched") performance, stability issues and even crash incidents.

progeCAD, like AutoCAD, offers several tools for addressing DWG data errors. Main among these tools is the AUDIT command:
http://docs.autodesk.com/ACD/2010/ENU/AutoCAD%202010%20User%20Documentation/index.html?url=WS1a9193826455f5ffa23ce210c4a30acaf-7855.htm,topicNumber=d0e19845

Regardless of the drawing origin, when system stability begins to degrade, always check the DWG quality using these tools. Occasional discussions on the CADDIT forum address these incidents directly with a number of good suggestions:
https://www.caddit.net/forum/viewtopic.php?p=1101

progeCAD offers comprehensive DWG drawing and editing at a fraction of the cost of AutoCAD, as shown above offering similar tools and completely compatible format. For a free progeCAD download visit CADDIT here (link).