                                   
     +==========================================================+
                  READHIST.TXT - R13c4 Readme History
     +==========================================================+
                                   
                           15 December 1995



This file provides the history of enhancements, fixes, and information
related to each of the R13 update releases.

=====================================================================-
CONTENTS
========-

  - R13c4 Update
  - R13c3 Update
  - R13c2 Update
  - R13c1 Update

The following list describes the R13c4 readme files:

README         Contains general information related to all platforms.
READPC         Contains DOS-specific and Windows-specific information.
READDOC        Contains documentation updates and revisions.
READDEV        Describes the text files that explain how to compile,
               link, and debug ADS and ARX applications, and tells
               where to find them.
READHIST       Describes the history of enhancements, fixes, and
               information related to each of the R13 update releases.


=====================================================================-
R13C4 UPDATE
============-

  - Windows 95 Release
  - ARX API Support
  - Ongoing Maintenance
  - Stability Enhancements
  - Documentation Updates


Windows 95 Release
==================-
AutoCAD Release 13c4 is a fully supported, logo-compliant application
for Windows 95. Earning the Windows 95 logo means that AutoCAD R13c4
is a well-integrated, 32-bit Windows 95 product. The release includes
the following features (some of these new features are also supported
on the other Windows platforms, as indicated in the chart below).

                              Windows 95  Windows NT   Windows 3.1x
32-bit performance            +           +            
Multiple AutoCAD sessions     +           +            
Long filenames                +           +            
OLE 2.0 with drag and drop    +           +            +
Windows 95 user interface     +                        
Uninstall                     +           +            +
UNC pathnames                 +           +            +
Email enabled                 +           +            +

32-bit performance
-------------------
AutoCAD Release 13 for Windows 95 was designed to take full advantage
of the increased performance and inherent benefits of the 32-bit
operating system. Running AutoCAD Release 13 under Windows 95
eliminates the 16-bit "thunking" layer that is present in Windows
3.1x, and results in roughly 20% improvement in raw performance. In
addition, AutoCAD for Windows 95 has the same system requirements as
under Windows 3.1x and also supports the High-Performance Driver for
Windows (WHIP) included with AutoCAD R13c3 for Windows.

Multiple AutoCAD sessions
--------------------------
Under Windows 95, more than one session of AutoCAD can be launched and
run simultaneously. The multiple sessions capability allows users to
work on more than one drawing at a time, plot and edit simultaneously,
or run applications or batch processes in the background.

Long filenames
---------------
The eight-character limit on filenames has been eliminated. Drawing
names can now contain up to 256 characters, including spaces.
Descriptive filenames also apply to other files such as menu files,
font files, and symbol files. A new system variable, LONGFNAME,
controls whether or not this feature is enabled.

OLE 2.0 with drag and drop
---------------------------
AutoCAD's OLE support has been upgraded to OLE 2.0 including both
container and object. In addition, drag and drop of OLE objects into
AutoCAD drawings is now supported providing an even smoother way to
share data.

Windows 95 user interface
--------------------------
The Windows 95 user interface shell is supported by Release 13.
AutoCAD takes on the correct appearance with regard to Windows 95 UI
components like buttons and dialogs and colors. AutoCAD's user
interface layout provides a very high degree of compatibility with
Microsoft Office applications so that a user can leverage his learning
across applications. Windows 95-style shortcut menus (right-button
activated) are also supported for certain items like OLE objects, the
drawing window, toolbars, and the command window.

Uninstall
----------
A complete installation of AutoCAD can now be uninstalled easily from
the Windows 95 Control Panel Add/Remove Programs item. An uninstall
icon is created for uninstalling from Windows NT or 3.1x.

UNC pathnames
--------------
Universal Naming Convention (UNC) paths to network drives and devices
are now supported. This feature allows users to specify a drawing name
on the network without referencing a drive letter. The operating
system will now locate the correct network server and path, freeing
the user from setting up drive letters ahead of time.

Email enabled
--------------
Users with MAPI compliant email programs can easily exchange and
review drawings electronically, without ever printing them. Drawings
can quickly and easily be routed as mail attachments via the File/Send
menu item.


ARX API Support
===============-
R13c4 also provides the base support for the AutoCAD Runtime Extension
(ARX), the new object-oriented application development environment for
Release 13. This C++ programming interface is supported in R13c4,
while development tools including documentation, header files,
libraries, and sample code will be distributed separately as the ARX
Software Developers Kit. ARX enables the new generation of Autodesk
applications such as ADE 2 and the Mechanical Desktop. In addition, it
provides the tight integration needed by independent developers for
creating the next generation of AutoCAD-based applications.


Ongoing Maintenance
===================-
Maintenance improvements, including feature additions, stability
enhancements, and performance improvements, round out the R13c4
release.

Feature Additions
-----------------
SOLPROF/SOLVIEW/SOLDRAW for R13 solids -- These three commands assist
the user in making drawings from AutoCAD ACIS-based solid models. The
SOLVIEW command creates new drawing views (floating viewports), and
the SOLDRAW command generates profile and section views of solids in
these viewports. The SOLPROF command creates profile images of three-
dimensional solids.

Single-line mtext editor -- A simple, single line editor for AutoCAD's
multiline text object and dimension text has been added.  This editor
is primarily intended for DOS customers who do not have access to the
multiline editor in AutoCAD for Windows.  The editor choice is
controlled by the MTEXTED system variable; setting this variable to
":lisped" will  enable the new editor.

New text style dialog -- A new text style dialog, DDSTYLE, provides
users with a more accessible method of creating, editing, and setting
text styles in AutoCAD.  Font styles and characteristics can all be
changed with the click of a mouse.  The dialog includes a preview tile
for displaying a graphic representation of the font and style.

ASILISP -- A new set of LISP functions for accessing external
databases, ASILISP, has been added to AutoCAD.  This set of functions
provides database hooks similar to  the ASI C interface that already
exists in the product.  ASILISP may provide a better prototyping
environment than C for some customers and perhaps one better suited to
the average person customizing AutoCAD.

ASE Drivers -- Two new database drivers for AutoCAD's SQL Environment
have been added:  Informix for DOS, and Oracle for Windows 3.1 and NT.
In addition, AutoCAD will extend its ODBC, dBASE 3 and 4, and FoxPro
support to Windows 95.

Direct distance entry -- Direct distance entry is a basic drafting
productivity feature that has existed in Autodesk's AutoCAD LT and
Generic CADD products.  It provides a very quick method for drawing
and editing to a specified size or distance.  Instead of entering
coordinate pairs, distance is input by moving the mouse in the desired
direction and entering a single distance value.  With the mouse locked
to orthogonal movements (ORTHO mode), this is an extremely fast method
of creating precision drawings.

Cue Cards -- Cue Cards have now been added to help new or intermediate
CAD users learn how to quickly apply their drafting skills to AutoCAD
one step at a time.  These cards provide the background needed to
understand the concepts, and step-by-step instructions on the most
common drafting operations.  In addition, the information is organized
by task and by feature.  Hypertext links to related tasks and the
detailed command reference save users time accessing needed
information.

Performance Improvements
------------------------
No regen on Window resize -- AutoCAD no longer performs a drawing
display regeneration when the drawing window is resized (via toolbar
or command window movement or application window size change) under
the Windows platforms.

Faster Object snap -- Object snap performance has been incrementally
enhanced on all platforms.


Stability Enhancements
======================-
The following issues have also been addressed by the R13c4 update.
Those items followed by a CS# refer to issues raised in the ACAD forum
on CompuServe.

+   General Issues
+   Geometry/Modeling Issues
+   Driver Issues
+   Windows-Specific Issues
+   WHIP Driver Issues
+   Customization and Developer Issues


General Issues
--------------
  -- There have been many enhancements to the use of xrefs with
VISRETAIN and incremental save (ISAVEPERCENT).

  -- Support for %% control codes in mtext and leaders has been added.

  -- A new value for DIMFIT has been added. If DIMFIT is set to 5, no
leader line is drawn from the dimension text to the dimension line.
See the R13C4NEW file for more information. (CS#49)

  -- Mtext objects can now contain more than 100 lines of text. This
resolves the issue about overlapping lines of text. (CS#48)

  -- The MTEXT command now accepts control characters as documented.

  -- When mlines are exploded, the resultant lines and arcs take on
the layer and linetype of the individual elements as assigned in the
multiline properties section of MLSTYLE dialog box, rather than the
properties of the current layer. (CS#141)

  -- The open cross option of MLEDIT works properly in a drawing that
has been imported with DXFIN.

  -- Perpendicular and Tangent Osnaps work on xlines, rays, and edges
of solids. (CS#138 and CS#137)

  --The drawing extents are correctly calculated in all drawings,
including those with scaled blocks containing leaders. (CS#177)

  -- When an exploded block (or drawing) is inserted in a model space
viewport, the objects are correctly placed. (CS#172)

  -- AutoCAD properly explodes unequally scaled blocks containing
polyline, minsert, mtext, and leader objects. (CS#180, #181, and #182)

  -- The WBLOCK command now writes out objects in the order they are
selected. (CS#152)

  -- The DDSELECT and DDRMODES commands now provide options for
setting Associative Hatch selection. (CS#123)

  -- DXFIN properly handles DXF files with xrefs.

  -- AutoCAD properly handles the opening of a drawing that contains a
reloaded xref. AutoCAD also correctly opens a drawing with xrefs where
VISRETAIN is set to 1.

  -- Polylines now display properly in paper space.

  -- Curved polylines with width now plot correctly.

  -- Polygon meshes now export with 3DSOUT.

  -- Tolerance objects in bound xrefs appear correctly in the drawing.

  -- The PURGE command no longer allows the purging of shape files
that are referenced by an existing font.

  -- DXFIX can now be used twice on the same DXF file without
consequence.


Geometry/Modeling Issues
------------------------
  -- AutoCAD now allows the extrusion of an R12 ellipse profile along
a 2D spline path.

  -- The EXTRUDE command now properly handles an extrusion with a very
small
taper angle. Extruding a circle along an ellipse no longer results in
a bad solid.

  -- The extrusion of a profile along non-rational splines works
properly now.

  -- The INTERFERE command correctly handles complex fillets within
solids

  -- AutoCAD correctly handles Boolean operations on regions and
polylines.

  -- The OFFSET command works correctly on spline objects.

  -- The INTERSECT command correctly handles operations involving a
cylinder and an elliptic cylinder.

  -- Revolving a region 90 degree about an X-axis results in the
proper geometry.

  -- Problems involving the hiding of a filleted solid with spline
patches have been resolved.

  -- FILLET no longer fails to blend a loop if the radius is equal to
the previous fillet.


Driver Issues
-------------
  -- Screen menu selection with the Rasterex driver has been
corrected.

  -- AutoCAD correctly allows access to dialogs after tablet
calibration.

  -- AutoCAD now allows digitizer I/O port initialization with REINIT
on interrupt driven digitizers.

  -- The ALIGN, ROTATE3D, and MIRROR3D commands chosen from the
digitizer template no longer cause an endless loop.


Windows-Specific Issues
-----------------------
  -- AutoCAD now ignores the selection of the Aerial View global icon
during a REGEN. (CS#155)

  -- Windows resources are no longer used up with repeated menu loads.
(CS#156)

  -- The Linetype Control widget in the Object Properties toolbar
properly displays the BYLAYER linetype. (CS#38)

  -- OLE objects are now recovered with the RECOVER command.


WHIP Driver Issues
------------------
  -- The speed of cursor movement has been improved.

  -- Full Plot Preview now displays OLE objects.

  -- The speed of gripped moves has increased.

  -- The color palette now updates correctly on viewport change with
TILEMODE=0.

  -- 16 color devices no longer render a blank screen.

  -- Render no longer fails at color depths greater than 256.

  -- AutoCAD now properly handles the following commands used in
sequence: RENDER, SAVEIMG, RENDER.

  -- The SAVEIMG and RENDER commands no longer display different color
palettes

  -- The SAVEIMG command no longer saves unwanted screen obstructions
(e.g. toolbars).


Customization and Developer Issues
----------------------------------
  -- The (menucmd "Pn=*") syntax now works properly in Windows. It
should be noted that this functionality may be removed from a future
release of AutoCAD. (CS#146)

  -- Menu swapping is now functional for all menu areas. It should be
noted that this functionality may be removed from a future release of
AutoCAD. (CS#150)

  -- AutoCAD now rejects the modification (with the entmod function)
of a pface mesh group code 70 from its normal value of 64 or 192 to a
value of 128. (CS#176)

  -- The AutoLISP and ADS setfunhelp function now works properly with
acedRegCmds->addCommand().  (CS#39)

  -- AutoCAD correctly compiles menus with lines ending in "+\".
(CS#30)

  -- The ads_arxloaded() function now returns the correct value.
(CS#210)

  -- Text can now be right-aligned in a dialog box text tile. (CS#11)

  -- The DDMODIFY.LSP application no longer contains a variable named
TYPE. This could have caused problems for other AutoLISP applications
that used the (type) function. (CS#76)

  -- The (entnext) function no longer returns the entity name of
deleted subentities. (CS#200)


Documentation Updates
=====================-
The R13C4NEW.HLP file (for Windows) and R13C4NEW.TXT file (for DOS)
describe the enhancements provided by the R13c4 update. The
Introduction section describes the following topics:

+   New and Enhanced Features
+   Windows 3.1, Windows 95, and Windows NT Features
+   Performance Tuning Features
+   Developer Documentation

This file also describes the changes made to the AutoCAD documentation
set for the R13c4 update. Please review this file to see if any of the
changes affect you.


=====================================================================-
R13C3 UPDATE
============-

  - Enhancements to R13c3b
  - Enhancements to R13c3a
  - Enhancements to R13c3


Enhancements to R13c3b
======================-
The R13c3b_c3 update addresses the following issue in addition to
those addressed by the R13c3a_c3 update.

  --  AutoCAD now properly handles the attaching and reloading of an
external reference file (xref) that contains non-continuous linetypes
when VISRETAIN is set to 1. Previously this could cause AutoCAD to
crash with the message "INTERNAL ERROR: !dbobji.cc@3263:
eNotOpenForWrite".


Enhancements to R13c3a
======================-
The R13c3a_c3 update addresses the following issues.

  --  AutoCAD now allows the selection of circles and arcs as input to
the DIMDIAMETER, DIMRADIUS, and DIMCENTER commands when the selection
point of the circle or arc falls within the area covered by a block
which contains attributes.

  --  The nentsel and nentselp AutoLISP/ADS functions now return the
correct entity name following the insertion of a block that contains
attributes. This problem may have affected some applications. At this
time, the only applications known to be affected are those from Genius
CAD Software.


Enhancements to R13c3
=====================-

General Issues
--------------
  --  BHATCH no longer detects objects on frozen layers.

  --  Unreferenced unnamed blocks are now purged automatically.

  --  Elliptical arcs can now be stretched.

  --  The SAVE command no longer changes the name of the current
drawing unless it is unnamed. It now writes a copy of the current
drawing to a new file.

  --  The time required to compile a menu file has been decreased.

  --  DXFIN properly imports a drawing with xref/bind that contains
complex linetypes.

  --  Multiple saves to a network drive work properly now.


Dimensioning Issues
-------------------
  --  DIMCONTINUE and DIMBASELINE do not recognize a previous
dimension after a UCS change. They also will not reference a
previously deleted dimension.

  --  The LEADER command now uses the correct arrowhead style and
honors all dimension overrides. The LEADER command correctly allows
the use of an exploded block as annotation.

  --  Leader objects now correctly honor the setting of DIMCLRT.

  --  The DIMTOL and DIMLIM dimension variables are mutually exclusive
Boolean system variables. Both may be false, but if one is set to true
the other is set to false.


Text and Font Issues
--------------------
  --  AutoCAD no longer ignores trailing spaces for right and middle
justified text.

  --  Mtext created in a rotated UCS in AutoCAD for Windows is now
properly oriented.

  --  The handling of bigfonts has been improved. The opening of R12
drawings with custom bigfonts are handled correctly and Unicode
symbols properly display with bigfonts.

  --  The TXT.SHX font has been modified to reduce the space following
the "i" and "l" characters.

  --  Special characters in BIGFONT.SHX now display correctly. For
example, the BIGFONT.SHX file properly displays the diameter symbol
when used with the ROMANS.SHX font.


ASE Issues
----------
  --  ASI and ASE can now use the PARADOX driver concurrently.

  --  The asi_setcfg function now correctly handles two arguments, as
documented.


Plotting and Driver Issues
--------------------------
  --  PSOUT now properly sizes text regardless of the text rotation.

  --  When plotting to a file with CMDDIA=0, AutoCAD correctly
overwrites the existing file (if any)

  --  The PostScript plot driver correctly handles the plotting of
dotted lines and dots in lines.

  --  The Summasketch III 1212 and 1218 DOS and wintab digitizer
drivers work properly now.


Customization, AutoLISP, and ADS Issues
---------------------------------------
  --  Menu swapping of the POP, AUX, and BUTTONS areas works properly
now. The pipe symbol "|" is now allowed in menu macros.

  --  Embedded comments are now acceptable anywhere in an AHP file.

  --  The AutoLISP function ai_propchk has been changed to c:ai_prop
so that it behaves similarly to other commands. This allows pressing
return to bring back DDMODIFY if selected from toolbar.

  --  Dimensions without a dimension style (from a pre-R13 drawing)
use a null string as the group code 3 value.

  --  Using the AutoLISP or ADS entmod function on an attribute
created in R12 or on a frozen layer works properly now.

  --  A semantic change to ssget "X" filtering: Previously, there was
no sense of literal matching -- the only filtering was via wildcards.
As a result, one could (for example) create a text string reading "Hi,
Joe!"; but attempting to filter on that string would fail, because the
comma was treated as a wildcard character. Now literal matching occurs
first; only if the literal match fails is wildcard matching attempted.

  --  Bit 3 (library search) of the getfiled function works properly
now.

  --  The message dialog that appears when loading an MNU file from
the MENU and MENULOAD commands no longer interrupts a script or
AutoLISP function.

  --  The use of a transparent command after an (ssget "F") no longer
causes an unhandled exception.

  --  (c:stats nil) properly turns off statistics logging.

  --  AutoLISP and ADS entget, now properly returns the group code 11.

  --  The ads_printf() function now works properly with a null string
argument.


=====================================================================-
R13C2 UPDATE
============-

  - Enhancements to R13c2b
  - Enhancements to R13c2a
  - Enhancements to R13c2
  - Additional Information -- R13c2


Enhancements to R13c2b
======================-
A small change in the AutoCAD R13c2 maintenance release and R13c2a
update is incompatible with some AutoCAD add-on applications. At this
time, the only applications known to be affected are Softdesk's Civil
and Building Design & Engineering product families. This update patch,
which applies to all platforms, upgrades a currently installed AutoCAD
R13c2 or R13c2a to R13c2b and resolves the incompatibility. Only
affected customers require this patch.

  --  The value of the SAVENAME system variable no longer contains the
.DWG extension.


Enhancements to R13c2a
======================-
--  The crosshairs no longer appear frozen during tablet configuration
or calibration when using the Wintab driver on Windows and Windows NT.


Enhancements to R13c2
=====================-
This section explains the problems that are fixed with the R13c2
update.

Dimensioning and Tolerance Fixes
--------------------------------
  --  DDIM now gives you the choice of stacked or longhand fraction
formats for both architectural and fractional units styles. You now
have a full range of choices over available styles for fractional unit
formats.

These choices are available through the DDIM Annotation dialog Primary
Units and Alternate Units options. They can also be specified with the
dimensioning system variables DIMUNIT and DIMALTU. Both DIMUNIT and
DIMALTU now accept values of 6 or 7, where the values are as follows:

      1   Scientific
      2   Decimal
      3   Engineering
      4   Architectural (stacked)
      5   Fractional (stacked)
      6   Architectural
      7   Fractional

The new values are not accepted by the LUNITS system variable because
the units formatting controlled by LUNITS cannot result in an MText
stack.

  --  The block name for the Right-angle arrowhead is now "OPEN90" to
make it consistent with the international versions of AutoCAD.

  --  Underscored commands are now recognized at the Dim prompt.

  --  Dimensioning commands now correctly handle instances where the
font file is not available by generating a text-free dimension block.

  --  DIMTEDIT no longer changes the position of the selected
dimension when the UCS is near to perpendicular.

  --  The DIMDIAMETER and DIMRADIUS commands properly handle dimension
placement using a DIMBLK of "DOT".

  --  The DIMANGULAR command correctly displays an error message for
an invalid object selection and returns to the object selection
prompt.

  --  The first point of a leader is placed properly when Ortho mode
is on.

  --  AutoCAD properly handles the canceling of the DIM:Leader command
at the "Dimension text <>:" prompt.

  --  The text in a tolerance object is correctly centered.

  --  AutoCAD now allows an ENDPOINT osnap on a tolerance object.


DXFIN, SAVEASR12, OPEN, and NEW Fixes
-------------------------------------
  --  The DXFIN command correctly assesses the contents of the current
drawing when making the decision to do a partial or full DXFIN.

  --  A partial DXFIN of an mline no longer causes the mline to lose
its scale.

  --  The SAVEASR12 command converts overlaid xrefs into attached
xrefs. If this causes a circular reference, the xref is rejected when
the drawing is opened.

  --  The SAVEASR12 command converts xlines and rays into lines by
clipping them based on the current drawing extents. If there are no
extents (for example, there are no objects other than xlines and
rays), the drawing is clipped based on the current view. If xlines or
rays pass through the current view, that portion is converted into
lines. Note: Due to the "infinite" nature of xlines and rays, they are
not taken into consideration when AutoCAD calculates the extents.

  --  The SAVEASR12 command now converts the background fill color of
mlines into the proper color solid-filled objects.

  --  When opening an R12 drawing with layers marked as DELETED
(typically converted from other CAD applications), AutoCAD places
objects on those layers on layer 0.

  --  The OPEN command's Find File, Search option now handles wild
cards in the following way: if the search string does not contain path
separators, the search will try to match either the full path or just
the file name portion of the path.

  --  When you start a new drawing (with the NEW command) after
opening a drawing as read-only, the new drawing's status is no longer
sets as read-only.

  --  The SAVENAME system variable is properly updated.


Object Creation and Editing Fixes
---------------------------------
  --  Many problems with the Object Grouping and Associative Hatching
features have been resolved.

  --  DDMODIFY properly modifies aspects of leader objects and
functions properly with R12 dimensions.

  --  The PERP Osnap interacts properly with spline endpoints.

  --  DDATTDEF now uses a default of 0,0,0 for the insertion point of
middle justified text if no insertion point is specified.

  --  The RECTANG command functions properly with Running Osnaps.

  --  AutoCAD properly handles the rejection of non-closable splines
by the SPLINEDIT command.

  --  The MLINE, XLINE, and RAY commands now display polar coordinates
(dist>ang) in the status bar when COORDS is set to 2.

  --  Mline objects can now be used as a reference when creating an
xline.

  --  MTEXT properly handles more than 256 text styles.

  --  Mtext objects can now be exploded into text objects.

  --  The MTPROP command correctly converts vertical text to
horizontal text.

  --  Ctrl+X properly deletes selected objects.

  --  The time required for AutoCAD to create layers has been reduced,
and objects on frozen layers now display properly in paper space.

  --  The BHATCH command correctly handles invisible attributes.

  --  The -GROUP (command line version) command properly applies wild-
card specifications.

  --  The text in a complex linetype scales properly.

  --  Edits performed on a group now affect the objects within the
group that are on a layer that is off.

  --  AutoCAD properly handles drawings with xrefs nested three or
more levels deep.


ASE Fixes
---------
  --  The ASE BIT and BIT VARYING data types work properly with the
Oracle 6 driver.

  --  In ASE, the datatypes DATE and TIME are now prohibited.

  --  The ASE Oracle 6 driver correctly handles tables with a FOREIGN
KEY REFERENCES constraint.

  --  ASE correctly processes SQL files containing a line with only
<TAB> or <SPACE>.

  --  AutoCAD correctly handles exploded blocks that contain ASE Link
Path names that already exist in the current drawing.


Rendering and File Export Fixes
-------------------------------
  --  The STLOUT command now uses the FACETRES system variable.

  --  By default the BMPOUT command creates a compressed BMP file. To
generate a non-compressed file, add the line 'BmpOutCompression=0' to
the [General] section of the acad.ini file. Compressed BMP files use
less disk space but may be unreadable by certain applications. The c0
and c1 releases of R13 always write compressed BMP files.

  --  Polyface mesh colors render properly.

  --  AutoCAD renders properly to a TGA file.


Viewing and On-line Fixes
-------------------------
  --  DDVIEW properly handles view names that include a hyphen.

  --  An Aerial View alert message now tells users that fast zooming
must be enabled in order to use the Aerial Viewer.

  --  The QuickTour feature runs properly when the TUTORIAL directory
is added to the support path.

  --  On-line help is now available during the CONFIG command.


Customization/Developer Fixes
-----------------------------
  --  AutoCAD now allows support paths of greater than 256 characters.

  --  The allowable string length of the <cfgname> and <cfgval>
arguments of the AutoLISP (setcfg) and (getcfg) functions has been
increased to 132 and 347 characters (respectively).

  --  AutoCAD now allows editing of toolbar icons.

  --  The sample application BMAKE is now included with AutoCAD.

  --  The new DCL attribute 'password_char' functions properly on DOS.

  --  The ADS functions ads_setcfg, ads_getcfg, ads_dictsearch, and
ads_dictnext work properly.

  --  The AutoLISP (set_tile) function correctly handles a value of ""
(the null string).

  --  The AutoLISP (grvecs) function properly honors XOR ink.

  --  The AutoLISP and ADS entmake functions now properly accept a
group code 48 in an entity definition list.

  --  1005 xdata group codes within an exploded block are correctly
updated to the new handles.

  --  The 2 group code (block name) of a dimension object is now
optional for the entmake function. If the block name is omitted from
the entity definition list, AutoCAD creates a new one. Otherwise,
AutoCAD creates the dimension using the name you provide.

-- The AutoLISP and ADS/ARX initget function can now provide localized
keywords. The following syntax for the keyword string allows input of
the localized keyword while it returns the 'language independent'
keyword:

      "<local1> <local2> <localn> _<indep1> <indep2> <indepn>"

Where <local1> through <localn> are the localized keywords, and
<indep1>
through <indepn> are the 'language independent' keywords. There must
always be the same number of localized keywords as language
independent
keywords, and the first language independent is prefixed by an
underscore.

For example:

      (initget "Abc Def _Ghi Jkl")
      (getkword "\nEnter an option (Abc/Def): ")

Entering 'A' returns 'Ghi' and entering '_J' returns 'Jkl'.

  --  When passing selection sets between AutoLISP and ADS/ARX
applications, the following should be observed:

    If a selection set is created in AutoLISP and stored in an
    AutoLISP variable, then overwritten by a value returned from an
    ADS or ARX application, the original selection set is eligible
    for garbage collection (i.e. it will be freed at the next
    automatic or explicit garbage collection).

    WARNING: This is true even if the value returned from the ADS/ARX
    application was the original selection set. For example:

      (setq var1 (ssget))
      (setq var1 (adsfunc var1))

    if the "adsfunc" ADS function returns the same selection set it
    was fed as an argument, then this selection set will be eligible
    for garbage collection EVEN THOUGH IT IS STILL ASSIGNED TO THE
    SAME VARIABLE!

    If you want the original selection set to be protected from
    garbage collection, then you must NOT assign the ads_name
    (selection set) return value of the ADS/ARX application to the
    AutoLISP variable that already references the selection set.
    Changing the example above to:

      (setq var1 (ssget))
      (setq var2 (adsfunc var1))

    prevents the selection set referenced by var1 from being eligible
    for garbage collection.


Additional Information -- R13c2
===============================-


Platform Independent Issues
---------------------------
  --  Release 13 does not currently perform automatic purging of
unreferenced anonymous blocks. Therefore you should periodically use
the PURGE command to reduce the number of unreferenced anonymous
blocks in a drawing. Anonymous blocks are used for hatch patterns and
dimensions. Each time you grip edit an associative hatch pattern,
AutoCAD generates a new anonymous block. Depending on your drafting
style you can end up with a large number of unreferenced anonymous
blocks, which needlessly increases the drawing file size.

  --  The menu file syntax has been modified for R13 AutoCAD for
Windows to provide additional functionality. These menu files are not
recognized by R13 DOS AutoCAD. If you save a drawing in Windows and
then open it in a DOS version, the menu may not appear as desired. Use
the MENU command to load the DOS menu file. AutoCAD for Windows
recognizes both the old and the new syntax.

  --  The Object Pager (OPG) is a new component of Release 13 C2,
which allows you to limit the amount of virtual memory that AutoCAD
uses to store the drawing currently being edited. When you enable the
object pager, AutoCAD keeps part of the current drawing in virtual
memory and part of it in the object pager's swap files. The object
pager shuttles the data back and forth between virtual memory and the
pager files, so that it always has what it needs in virtual memory.

If you are editing large drawings that are causing heavy disk swapping
or are causing the system to crash or otherwise act in an unstable
way, then you might benefit from enabling the object pager. This will
reduce the strain on the system's swapping mechanism and should
stabilize and perhaps speed up AutoCAD R13.

The object pager is controlled by the MAXOBJMEM variable. This
variable specifies approximately how much virtual memory AutoCAD will
allow the drawing to take up before it starts paging the drawing out
to disk. For example, if MAXOBJMEM is set to 1000000 (one million),
then AutoCAD will limit the current drawing's virtual memory use to
1,000,000 bytes.

You can set the MAXOBJMEM variable by entering MAXOBJMEM on the
command line. You can also set the environment variable ACADMAXOBJMEM.
Note that environment variables can be specified in the acadenv.ini
file as well as in the actual environment. See your Installation Guide
for information on setting environment variables.

The default value of MAXOBJMEM is 0, which disables the object pager.
When MAXOBJMEM is set to a negative value, 0 or to 2,147,483,647, the
object pager is disabled. When MAXOBJMEM is set to any other value,
the object pager is enabled and that value is used as the upper limit
for how much virtual memory the pager will use. We recommend setting
MAXOBJMEM to the approximate size of your system's physical memory.
For example, if your system has 24MB of RAM, you could set MAXOBJMEM
to 24000000.

The object pager creates two temporary swap files.  These swap files
use a naming scheme of MPGR<nnnn>, where the <nnnn> varies per
session. These files are created when you begin a drawing and are
destroyed when you exit. By default, they are created in the directory
pointed to by the ACADPAGEDIR environment variable. If that variable
is undefined, they are created in the AutoCAD temp directory. If you
reboot the system without exiting AutoCAD, these files won't be
properly deleted, so you should delete them yourself. Do not attempt
to delete them from within AutoCAD!

The object pager is separate from the other pager used by AutoCAD. The
other pager uses different swap files (PG*) and other variables
(ACADMAXMEM and ACADMAXPAGE) to control its memory usage. The one
thing both pagers have in common is that they both use ACADPAGEDIR to
decide where to place their swap files.

If ACADPAGEDIR is set to an invalid directory, AutoCAD disables the
object pager and displays a warning message. You should change
ACADPAGEDIR to point to a writeable directory.

If you change MAXOBJMEM, the pager will not turn on (or off) until you
exit the current drawing and enter another. Once the pager is turned
on (or off), it remains in that condition for the duration of that
drawing session (until the next NEW or OPEN). However, if the pager is
on, then changes to the value of MAXOBJMEM (to raise or lower the size
of the virtual memory used) are noticed immediately.

  --  As a side effect of the SPLINEDIT Move vertex option, the fit
points which define the spline, if any, are purged.


=====================================================================-
R13C1 UPDATE
============-

  - Enhancements to R13c1a
  - Enhancements to R13c1
  - Additional Information -- R13c1


Enhancements to R13c1a
======================-
  --  Attaching an xref drawing with missing nested attachments or
opening a drawing with missing nested attachments works correctly. The
same is true for drawings that are overlayed.

  --  Editing an associative hatch's boundary when the hatch pattern
is on a frozen layer works correctly.

  --  Performing a DIMTEDIT/LEFT or RIGHT on a dimension in a
paperspace viewport works correctly.

  --  Switching to paper space when an object's grips are active works
correctly.

  --  Mline styles are now associated with the correct layers in all
cases.

  --  When running the DOS version on fast PC's such as 90Mhz or
faster Pentium computers, AutoCAD for DOS was overzealous in polling
the keyboard, possibly leading to a performance slowdown. This has
been corrected (this problem is not related to the Pentium floating
point problem).


Enhancements to R13c1
=====================-
  --  PostScript and TrueType font mappings are now included in the
ACAD.INI file.

  --  Anonymous group definitions within xrefs correctly translate
into new definitions.

  --  Group name definitions within block references and xrefs are no
longer retained within the drawing database which allows access to
these names by editing commands. Group naming conflicts within block
references has been corrected.

  --  The speed of group selection has been increased.

  --  GROUP Add correctly adds entities removed from group membership
via GROUP Remove.

  --  The combo boxes are now accessible after respacing buttons on
the Object Properties toolbar. AutoCAD now correctly handles the
creation of a custom toolbar and the modification of a toolbar flyout.

  --  Circles drawn perpendicular to the WCS display the correct
linetype.

  --  The BREAK and TRIM commands properly duplicate associated xdata.

  --  A semicolon in the ***AUX and ***BUTTONS menu sections is now
correctly interpreted as a return in menu macros, and the plus sign is
now a valid character for screen menu labels. A backslash in a menu
macro in the ***AUX menu section is now correctly replaced with the
coordinates of the pick point.

  --  The AutoLISP (grvecs) function properly highlights entities as
specified.

  --  The ADS function ads_printf() properly responds to format
strings.

  --  In ARX ADS, the ads_command(RTNONE) function properly cancels a
currently running AutoCAD command.

  --  Trimming and grip-copying splines now works correctly.

  --  A full plot preview now displays OLE objects properly.

  --  AutoCAD now imports DDE data correctly.

  --  AutoCAD properly saves the status of "Keystrokes" when the
Preferences dialog is accessed from the Command Window or the Text
Window.

  --  PSOUT now correctly renders 8-bit text objects on DOS.

  --  RENDER properly uses subentities' colors in a 3Dsolid, resulting
in more consistency between SHADE and RENDER.

  --  The BHATCH dialog User, Normal, Inner and Outer options now
return the proper values to the HPNAME system variable in localized
versions of AutoCAD.

  --  Hatch patterns beginning with letter used for the "User" hatch
pattern option (such as 'U' on US English versions) are now valid.

  --  DDCHPROP now properly handles a selection set of objects with
varying thickness or linetype scale.

  --  Coordinate display and view centering problems with the Aerial
Viewer have been fixed.

  --  Long path names in the Open Drawing dialog box do not force the
Read Only check box to be selected.

  --  Transparent Help is disallowed from AutoLISP on DOS - Calling
for help by typing 'HELP as a prompt generated from an AutoLISP or ADS
program has been disabled for DOS only. You may still ask for help in
these situations in AutoCAD for Windows. Note that this means that the
AutoLISP function (setfunhelp) and the ADS function ads_setfunhelp()
are useless for DOS, since the information they register will never be
used.


Additional Information -- R13c1
===============================-
  --  The relative sizes of numbers in stacked fractions are now based
on the DIMTFAC system variable (in the same way that tolerance values
use this system variable).

  --  Unloading of ADS and ARX apps fails on Windows if you are using
SHARE.EXE. To maintain file protection in a multiuser environment, use
VSHARE.386 instead of SHARE. You have three options, each explained in
greater detail below:

  - Use VSHARE.386 instead of SHARE.EXE
  - Continue to use SHARE.EXE
  - Use neither SHARE.EXE nor VSHARE.386

VSHARE comes with newer Microsoft Windows products such as Office,
Word, Windows for Workgroups, etc. VSHARE is a total replacement for
SHARE.EXE, so you don't need both. Take SHARE.EXE out of your
AUTOEXEC.BAT, and add the following line to the [386Enh] section of
your SYSTEM.INI file:

      device=vshare.386.

Continuing to use SHARE is not a problem assuming that you don't care
about being able to unload ADS or ARX applications. If you try to
unload an application with SHARE loaded, the unload fails cleanly with
a command line notice of the failure to unload -- AutoCAD continues on
without a problem.

It is also possible to run AutoCAD without loading SHARE or VSHARE.
Doing so will allow you to unload ADS and ARX applications but does
have the following consequences:

  - You are unable to use ASE and ADE without SHARE or VSHARE
  - Many Microsoft programs require SHARE or VSHARE to be loaded
  - File protection in a multiuser environment is compromised


  --  The ACAD.PGP file is common to all platforms, however it
references external commands that work only in DOS (such as CATALOG,
DIR, EDIT, and TYPE). These are not meant to work on other platforms
such as Windows.

  --  The diskette version of AutoCAD Release 13 contains basic
customization tools such as AutoLISP and associated documentation. The
programming interface files for ADS and ASI development, as well as
all the advanced customization documentation, are only available on
the CD version of AutoCAD Release 13. This electronic documentation is
part of the complete documentation set available on the CD version.

