    *********************************************************************
    **                                                                 **
    **         A u t o S u r f     R E L E A S E  2.1_c1               **
    **                                                                 **
    *********************************************************************

This file contains last-minute items of information that did not make
the printed documentation.

========================================================================

WHAT PROBLEMS DOES IT FIX?
==========================
 - AutoCAD R13_c2 Path Names
 - Installing AutoSurf R2.1_c1 with AutoCAD R13_c2
 - Bug Fix
 - File Spec
 - POPADD.EXE
 - AutoSurf Windows Menu


AutoCAD R13_c2 Path Names
=========================
This c1 release addresses the AutoCAD R13_c2 change of path
names from R13_c1.  The following two path names were changed
in the AutoCAD default install.

  OLD                           NEW
  ========================================
  c:\acadr13                    c:\r13

  c:\...\common                 c:\...\com

This change had an effect on the AutoSurf installation.  The new
AutoCAD paths have been updated in the AutoSurf R2.1_c1 installation.


Installing AutoSurf R2.1_c1 with AutoCAD R13_c2
===============================================
The following should be noted about upgrading to AutoCAD R13_c2:

  If you are installing AutoCAD R13_c2 as your first installation
  of R13, or you are doing a full reinstall of R13_c2 by using the
  complete set of 3.5" disks or CD, your default AutoCAD directories
  will be established with the new names.  The AutoSurf installation
  support paths will match those of AutoCAD R13_c2, and you can
  proceed with a normal installation.

  If you already have R13 installed on you system and you are 
  upgrading to R13_c2 by installing the c2 patch upgrade, the OLD
  directory structure will not be changed for you.  As a result
  the default install support path of AutoSurf R2.1_c1 will not
  match that of your existing AutoCAD directory structure.
  When installing AutoSurf R2.1_c1 you will need to change all
  directory defaults of c:\r13 to c:\acadr13, and all references
  of c:\...\com to c:\...\common

Bug Fix
=======
There was a bug fix for the TUBESF command which caused AutoCAD to 
exit when the command was executed on a 2 point line or, 2 point
polyline.

File Spec 
=========
There were some last minute changes to the installation that 
affected the Installation Guide File Spec.  AutoSurf has gone from
two executables to one executable for both platforms which will be 
c:\asrf\asrf.arx.  As a result of this, and some other changes, the 
file spec that was printed in the Installation Guide will not match 
the files that were actually installed on your hard drive.

Here is a partial listing of the new file spec:

                             ASRF
                           asrf.arx
                          readme.asf
                           asrf.pwd
                         as_patch.exe
                         as_patch.cfg
                         as_patch.log
                              |
                           ASCOMMON
                              |
    --------------------------------------------------------
    |            |                        |                |
 ASBONUS       SAMPLE                  TUTORIAL         SUPPORT


Customizing Menus - POPADD.EXE
==============================

Overview
--------

POPADD.EXE is a standalone executable located in the ASRF\ASCOMMON\SUPPORT
directory.  POPADD.EXE allows easy integration of a pulldown menu (henceforth
referred to as SOURCE menu) into an existing menu file (henceforth referred to
as TARGET menu).

POPADD.EXE allows you to add your own pulldown menus or menus from other AutoCAD
applications into a single menu file.

POPADD.EXE appends a DOS formatted SOURCE menu to any valid AutoCAD TARGET
menu.  POPADD will append the SOURCE menu file to the bottom of the TARGET
menu file and place the SOURCE pulldown into the first open slot in the
TARGET menu pulldown.  For example, if the last pulldown menu in the TARGET
menu is POP10, and the SOURCE menu contains two POP menu sections, they will be
placed in POP11 and POP12.  The POP location defined in the SOURCE menu does not
affect its placement.


Source Menu
-----------

The SOURCE MENU must be in the menu file format as follows:

***POP#
[Menu label]
[Mycommand]_mycommand
    .
    .
    .
***SCREEN
    .
    .
    .

***TABLET
    .
    .
    .

 AutoSurf includes a SOURCE menu for your convenience:
     ASRF\ADCOMMON\SUPPORT\ASRF.MNU [Contains pulldown definition only]

Running POPADD
--------------

1. Create your SOURCE menu or locate the supplied SOURCE menus.

2. Locate your TARGET menu.

3. Make a backup copy of your TARGET menu (in case of problems you will still be
   able to load the backed up TARGET menu file).

4. Change directories to the location of POPADD.EXE.

5. Exit from AutoCAD (i.e. do NOT use the Shell command). Execute the POPADD
   command at the DOS prompt when AutoCAD is NOT currently running
   Enter the following command, substituting SOURCE and TARGET with appropriate
   menu names.

   POPADD.EXE [SOURCE menu] [TARGET menu]

6. Start AutoCAD.

7. Load the modified TARGET menu file with the .mnu extension to force the menu
   file to recompile.The new pulldown from the SOURCE menu should be the
   farthest pulldown on the right.

   If the new pulldown does not display, unload ALL menus with the Menu
   command, and then load the modified TARGET menu.  The SOURCE menu
   should now be displayed as the last pulldown menu on the right.

Example:
--------

To add the AutoSurf pulldown menu to the AutoCAD R13 Full Windows menu, enter
the following:

POPADD  C:\ASRF\ASCOMMON\SUPPORT\ASRF.MNU  C:\R13\WIN\SUPPORT\ACADFULL.MNU

The basic AutoCAD menu looks like this:

 File  Edit  View  Draw  Construct  Modify  Data  Options  Tools  Help

After executing the POPADD command above, the pulldowns will now look like this:

 File  Edit  View  Draw  Construct  Modify  Data  Options  Tools  Help  AutoSurf

Notes
-----

Some AutoSurf pulldown menu functions are dependent on AutoLISP routines
in the ASRF\ASCOMMON\SUPPORT\ASRF.MNL file.  To load these functions
automatically do one of the following:

1. Append ASRF.MNL to your TARGET.mnl or copy ASRF.MNL to TARGET.MNL
   The name of the mnl file must have the same name as the TARGET menu
   file.
   For example, TYPE ASRF\ASCOMMON\SUPPORT\ASRF.MNL >> MYMENU.MNL

2. Add the following statement into the ACAD.LSP file, including
   parentheses and quotation marks:

   (load "C:\\ASRF\\ASCOMMON\\SUPPORT\\ASRF.MNL")

For more information on customizing your menu see "Menu File Structure"
and Execution" in the AutoCAD Customization Guide


AutoSurf Windows Menu
=====================
When running the AutoSurf Windows version for the first time, you 
will need to load the ACAD.MNU file manually.  Please use the 
AutoCAD MENU command.


======================================================================

The following is information that was copied from the R2.1 readme
that still applies to R2.1_c1

======================================================================


    CONTENTS
   ==========

	AutoSurf R2.1
	 - Loading/Unloading of AutoSurf R2.1
	 - Authorizing AutoSurf R2.1
	 - ASRF.PWD
         - Splines
         - Groups
         - Obsolete Keywords
         - AutoSurf R2.1 Toolbars
         - AutoSurf R2.1 Windows Help File
         - AS_PATCH.EXE 
         - SHARE.EXE
         - Known Problems

	Tips, Techniques, and Limitations

	Known Problems

	Questions and Answers

====================================================

About AutoSurf R2.1
 
 Loading/Unloading of AutoSurf R2.1
 ==================================
 Repeated loading and unloading of the AutoSurf executable, during a
 single session is discouraged. Instabilities resulting from the
 repeated load/unload conditions may cause an immediate exit out of
 AutoCAD.
 
 Authorizing AutoSurf R2.1
 =========================
 When AutoSurf R2.1 is first installed, please use the command line
 to load AutoSurf into AutoCAD as opposed to using the AutoSurf menu.
 For more information, please refer to the AutoSurf R2.1 Installation
 Guide under the section Authorizing AutoSurf.

 ASRF.PWD
 ========
 AutoSurf requires an authorization code to run, which is supplied
 by your dealer.  This authorization code is stored in the AutoSurf
 password file asrf.pwd.  AutoSurf uses asrf.pwd to track current
 AutoSurf users and determine whether additional users can start
 AutoSurf.  In a network installation, whenever a user attempts to load
 AutoSurf, AutoSurf compares the number of licenses in use with the
 number of licenses purchased.  If a license is available, the user is
 allowed to start AutoSurf, and the user is added to the list of current
 users.

 If for some reason, you are unable to load AutoSurf you may see the
 following message:
  
  Initializing...Error opening the asrf.pwd license file. 

 If you see this message, your password file has been corrupted.
 We recommend you take the following steps immediately after installing
 AutoSurf Release 2.1 to prevent this from happening to you in the
 future.

 1. Start AutoCAD Release 13.
 2. Initialize AutoSurf and give your authorization code.
 3. Quit out of AutoCAD at this point.
 4. Locate your asrf.pwd file, which by default is located in 
    c:\asrf\asrf.pwd.
 5. Make a backup of this file by copying it to some other name, for
    example:
    
     copy asrf.pwd pwd.bak

 If you should ever encounter the message, 
 
     Initializing...Error opening the asrf.pwd license file. 
 
 all you'll need to do is shell out of AutoCAD, and copy the 
 backup pwd file to the original, for example: 

     copy pwd.bak asrf.pwd

 Then you will be able to initialize AutoSurf Release 2.1 without 
 a problem.
 
 Splines
 =======
 Splines are now a native AutoCAD entity. The AutoSurf commands 
 that create splines will now create AutoCAD splines. The splines
 created in previous versions of AutoSurf will automatically be
 converted to AutoCAD splines when the old dwg/dxf file is loaded
 and AutoSurf is loaded.

 AutoCAD R13 now provides an ellipse entity. The AutoSurf ELLIPSE3D
 command now creates a ellipse instead of a spline in the shape
 of a ellipse.

 Since the display of splines is now completely controlled by AutoCAD,
 the Tolerance option for the AutoSurf EDITSP command is obsolete.

 Groups
 ======
 Groups are now native to AutoCAD. The AutoSurf commands that
 create groups of entities will now create AutoCAD groups. The
 groups created in previous versions of AutoSurf will automatically
 be converted to AutoCAD groups when the old dwg/dxf file is loaded
 and AutoSurf is loaded.
 
 The AutoSurf GROUPAS command has been replaced by the AutoCAD
 GROUP command.

 Selection by groups has changed.  Please see the AutoCAD manual
 for a description of selecting by groups.

 The Group option for the PURGESF command is now obsolete since
 AutoCAD controls the memory for groups.

 Obsolete Keywords
 =================
 The following command keywords have been removed from the AutoSurf
 R2.1 product.

 EDITSP, Tolerance - Spline tolerance now controlled by AutoCAD R13.
 PURGESF, Group - Groups are now created by AutoCAD R13.
 SURFVAR, Assplineconv - Splines now created by AutoCAD R13.

 AutoSurf R2.1 Toolbars
 ======================
 AutoSurf 2.1 for Windows includes two sample AutoSurf R2.1 toolbars, 
 "AutoSurf Create" and "AutoSurf Edit".  These optional toolbars provide
 quick access to surface creation and surface editing commands.

 For this release of AutoSurf R2.1 for Windows, you can quickly open 
 the AutoSurf R2.1 toolbars by issuing the ASTOOLBAR or the AutoLISP "Q" short
 key commands on the command line.  Entering either command on the command 
 line will menu load the asrf_tb.mnu and display both the "AutoSurf Create" 
 and "AutoSurf Edit" toolbars.  Note that the next Windows release of AutoSurf
 (R3.0) will load the toolbars from the AutoSurf R3.0 menu and the ASTOOLBAR 
 and/or the Q AutoLISP commands may be discontinued.

 You have the option of adding the AutoSurf toolbar access to the acad.mnu.
 However, if you make a mistake, the ACAD.MNU file may not load properly. 

 WARNING -- modify the acad.mnu at your own risk.  If you make a mistake
 the acad.mnu file may not load properly.

 Adding AutoSurf 2.1 toolbars in the acad.mnu file
 -------------------------------------------------
 1. Locate your Windows acad.mnu (by default it's in the
    C:\acadr13\win\support directory).

 2. Make a backup copy of your acad.mnu file (in case of problems).

 3. Use an ASCII editor like MS EDIT or a word processor (saving as ASCII Text)
    like MS Word (saving in Text Only format) for editing.  See the NOTE
    at the end of this section. 

 4. Locate the AutoSurf pulldown menu "POP8"in the acad.mnu.

 5. After the following line
    [<-Unload AutoSurf]^C^C^P(ai_unloadasurf);^P

    Add the following two lines
    [--]
    [Toolbars]^C^C_astoolbar;

Here is an example of the acad.mnu file before and after the 
modifications:

Before
------
[->Utility]
[Aug Lines Out...]^C^C_outputaug;
[MOD In...]^C^C_modin;
[MOD Out...]^C^C_modout;
[Purge Surface]^c^c_purgesf;
[--]
[Load AutoSurf]^C^C^P(ai_loadasurf);^P [<-Unoad 
[Unload AutoSurf]^C^C^P(ai_unloadasurf);^P

// 
//   Begin AutoCAD ToolBars 
// 

***TOOLBARS
**STANDARD_TOOLBAR

After
-----
[->Utility]
[Aug Lines Out...]^C^C_outputaug; 
[MOD In...]^C^C_modin; 
[MOD Out...]^C^C_modout;
[Purge Surface]^c^c_purgesf;
[--]
[Load AutoSurf]^C^C^P(ai_loadasurf);^P [<-Unoad 
[Unload AutoSurf]^C^C^P(ai_unloadasurf);^P 
[--]
[Toolbars]^C^C_astoolbar;

//
//   Begin AutoCAD ToolBars
//

***TOOLBARS
**STANDARD_TOOLBAR

 Instructions continued
 ----------------------
 6. Now save your changed file acad.mnu and restart AutoCAD.

 7. The menu should recompile automatically as the acad.mnu file is loaded.

 8. The last menu item in the AutoSurf pulldown menu should be "Toolbars".

 NOTE:
     For more information on customizing your menu see "Menu File Structure" 
     on page 86 of the AutoCAD Customization Guide and "Pull-Down and Cursor 
     Menus" on page 105 in the AutoCAD Customization Guide.

 AutoSurf R2.1 Windows Help File
 ===============================
 To use the AutoSurf R2.1 Help file in the Windows environment, you
 must bring up the AutoCAD help file, and then from the File pull
 down menu, use the open option to load up the ASRF.HLP file, 
 located in c:\asrf\ascommon\support by default.  This only applies
 to the Windows product, your AutoSurf DOS help file has been 
 merged with the AutoCAD help file.

 AS_PATCH.EXE
 ============
 This program is run at the end of installation.  Its  main purpose
 is to append some of the asrf support files onto the end of some of the 
 AutoCAD support files. The AutoCAD files it touches are the ACAD.MNU, 
 ACAD.MNL, ACAD.LSP, and the ACAD.AHP file.  The as_patch.exe program reads 
 the as_patch.cfg file for product, version, and file location information. 
 This file is created at install time from the information given by the 
 user while installing.  The as_patch program will backup all files it 
 touches before making any changes to the files.  The naming convention 
 for backup files is as follows:
           acad001.mnu
           acad001.ahp
           acad001.lsp
           acad001.mnl

 The format of the as_patch.cfg file is as follows:
 ; install or deinstall
 INSTALL  
 ;product name and release
 AUTOSURF R2.1  
 ;product base directory
 c:\asrf\ascommon\support 
 ;AutoCAD support file directories
 c:\acadr13\common\support 
 c:\acadr13\dos\support
 c:\acadr13\win\support

 If for any reason you need to run as_patch.exe from the command line you
 will have to have the as_patch.cfg file.  You can also have the as_patch.exe
 file remove the changes it made by changing the line in the as_patch.cfg 
 file from INSTALL to DEINSTALL and running the as_patch program from the 
 DOS command line. The syntax for running the as_patch program from the 
 command line is as follows:
	   as_patch as_patch.cfg

 SHARE.EXE
 =========
 NOTE: The following section was taken from the AutoCAD R13_c1 
       readme file, and was added here as it has significant
       impact on the loading and unloading of AutoSurf R2.1.

     -- Unloading of ADS and RX 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 RX 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 RX 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

 Known Problems
 ==============
 *The SPLINE3D command will continue to create the exact same spline
  as it would in R2_c1 when the same command settings and input
  data is used. It will not produce the exact same spline as the
  AutoCAD SPLINE command does, because the commands defaults are different
  and the end tangency's will be different.

 *C0 splines with less than 6 control points may display invalid on
  the screen, but the data of the C0 spline is correct.

 *When an entity is modified by an AutoSurf command, it is currently
  being removed from all groups that it belongs to.

 *The bonus translator, MOD2IGES, fails when the mod file contains
  splines.

======================================================================

The rest of the information contained in this file is information that
was copied from the R2_c1 readme that still applies to R2.1

======================================================================



Tips,  Techniques, and Limitations


Tips
====

DISPLAY  
*When setting the default U & V line display to 2, certain types of 
 surfaces will not be displayed in a manner that makes obvious sense. Surfaces 
 like cones, spheres, and cylinders will appear incomplete because the 
 beginning U and ending U (same with V) will be displayed at a common 
 location.

TOLERANCE 
 *The system tolerance can significantly affect results of surfacing operations.
  Users should always be aware of the Metric and Inch settings especially when
  translating data from other systems. Use ASSYSTOL to set the system tolerance
  to a value that is properly proportioned to model size. Read Chapter 2, AutoSurf
  Fundamentals for complete details.
 
C0 SURFACES
 *The abrupt corners of a C0 surface may not be obvious to the eye.  A change
  in tangent direction of as little as 0.5 degrees is considered C0.  If a C0
  continuous surface is not obvious, use the "Feature lines" option of the
  FLOWSF command to see where the discontinuities occur.

FILLETSF 
 *The fillet radius should not exceed the radius of curvature of 
  either surface. We cannot trim a surface twice with exactly the same 
  operation (or very close one). For example, if the user already trimmed a 
  surface with FILLETSF, he should not do the same FILLETSF with TRIM option 
  again. If he uses a new fillet radius, the new radius should be 
  substantially different from the old one. 

EDITBORDER
 *The Slab option of the EDITBORDER command creates a closed border on the
  selected surface(s) that follows the natural boundary of the slab.  This
  has an "inverting" effect on any closed borders already on a trimmed surface.
  Any outer boundaries which are on the surface will become inner boundaries
  (or holes) and holes in the trimmed surface become outer boundaries.

REFINESF
 *Although REFINESF may indicate that no change was made in the patch count
  of a surface, it is important to remember that REFINESF can affect other
  characteristics of the surface.  REFINESF may reduce the order, change
  number of control points, eliminate an offset, and make a surface no
  longer rational.  This information can be checked with the LISTAS command.
 
AUTOMATIC TRIMMING 	
 *Users can create trimmed borders on surfaces that intersect one another or
  by projecting or filleting. It is important to note that using these borders 
  for other surfacing functions (SWEEPSF, LOFTSF) will in most cases create 
  improper or unexpected results, or not work at all. 
  Users should make it a practice to follow these rules:
   * All borders must be closed (no gaps).
   * New borders should not overlap (lay on top of) existing borders.
   * You cannot join or extend trimmed surfaces.
   * Trim borders should not self intersect ( >< )

AME2SF - bonus command
 *If you plan to convert the AME solids to the trimmed surfaces, it is better
  to set the AME variable SOLWDENS to be greater than 1 before you create
  solids. Increasing the SOLWDENS variable to a higher value will help the 
  automatic trimming option to trim the surfaces.
 *You should always try the automatic option first unless you only want to trim 
  curves and slab surfaces. If the automatic option cannot trim surfaces properly, 
  it will give you slab surfaces with trimming curves so you can project the
  curves and then trim the surfaces manually.


Techniques
==========

 *INPUT DATA. When surfacing, remember that you create surfaces from either 
  wireframe or other surfaces, not thin air. If the wireframe sections you 
  are using to create a surface are "messy" the surface probably won't be 
  any better. If you are using polylines as input, pick on them to display 
  the grip handles, and visually inspect for too many points, or for areas 
  where the line comes back on itself. If the line has too many points, 
  use REFINE3D.

 *INPUT DATA. Often when you receive wireframe data from other sources, 
  you will need to join, or break the data before surfacing. Breaking at
  the sharp corners, or at places of rapidly changing curvature, and then
  surfacing the wireframe can save time in the long run.

 *INPUT DATA. It's possible that you will receive more data than you need
  to surface certain areas. For example, if you are given 10 sections but
  you know that it is a straight blend from the first section to the last
  then by all means use the RULESF command picking just the first and last
  sections. You can measure the distance from the other sections to the
  surface with DIST3D.

 *KEEP IT SIMPLE. You must surface the part for the detail required. for
  example, if you were to surface a part for future NC operations, and 
  there are some drilled holes in the part, you probably do not need to 
  surface these holes in your part. They can be shown by centerlines of the 
  drill. (For rough and finish NC you probably do not want holes in your 
  surface, drill the holes as a later operation)

 *KEEP IT SIMPLE. Again, the simpler the surface created, the faster 
  operations such as meshing of flow lines will work. Picking 100 
  sections to create a surface when 10 would have sufficed is a waste
  of computer resources.

 *QUALITY CHECKING. If you create a surface, and it happens to be 
  incorrect, don't create a new surface from the bad one.  The new 
  one probably will not be any better. Before using an existing 
  surface to create new surfaces, make sure that the existing surface 
  meets the requirements you need for the part. (Tolerance, shape...) 
  You can check surfaces by cutting sections through them, and examining 
  the sections. (SECTAS)
  
 *QUALITY CHECKING. It is a good idea to cut sections (SECTAS) through 
  your completed part to verify quality. If two sections through two
  surfaces meet and create a sharp corner, where smoothness is required, 
  then the surfaces are probably not tangent. 

 *SHADING. Shading your part will help to verify for smoothness and for
  large gaps. Remember to create the polyface mesh first (DISPSF).

 *TOLERANCE. Remember to keep your tolerance in line with the job
  requirements. If your part is not real critical, loosen up the 
  system tolerance; it could allow your work computations to go
  faster.


Limits/Additional data By Command
=================================

Important feature limitations and constraints
 *Offset surfaces cannot be joined with JOINSF
 *Rational surfaces are not supported by all data exchange formats 

AME2SF - bonus command
 *This command can only convert the solids with BFile created by AME R2 to 
  trimmed or untrimmed surfaces. See SOLPURGE command in the AME 2 Reference 
  Manual for additional information on BFile entity.
 *The Manual option converts the edge on the solids to NURBS curves and 
  the surfaces of solids to untrimmed NURBS surfaces. The Autotrim option 
  converts solids to trimmed(or untrimmed) NURBS surfaces.
 *The colors of NURBS surfaces are always the same as the color of the top 
  level solid even if the original composite solids have different colors.

BLENDSF
 *You can only blend with weights if blending to exactly two surface edges
  or two sections of augmented data.
 *Can not blend to trim surface borders.

DISPLAY
 *This command is not valid in Paper Space.  This is also true for the
  short keys of 6, 7, 8, dxz, dyz and i since the viewing direction can only
  be 0,0,1 in paper space.  The 5 and dxy will only fit the paper space
  viewport when in paper space.

FILLETSF
 *When using automatic trimming, the flow lines on the surface should not self 
  intersect. It is also important to note that trims cannot cross over seams 
  and poles.
 *Open trim curves will be extrapolated until they intersect the surface edge.
 *Selection indicates the portion of the surface that should be kept when 
  using the 'trim' option.
 *In cases when the fillet radius specified is greater than the radius of 
  curvature of either of the input surfaces, a self intersecting or 
  overlapping surface may result.

INTERSF
 *When using automatic trimming, the lines on the surface should not self 
  intersect. It is also important to note that trims cannot cross over seams 
  and poles.
 *Open trim curves will be extrapolated until they intersect the 
  surface edge(s).
 *Selection indicates the portion of the surface that should be kept when 
  using the 'trim' option
 *This command does not work under the conditions where the input surfaces 
  intersect theoretically or are tangent to one another. 

JOINSF
 *This command will not function when offset surfaces have 
  been selected as the input data. 
 *This command will not function when Trimmed 
  Surfaces have been selected as the input data. See the Fundamentals Chapter 
  for additional information on Trimmed surfaces.

LOFTSF
 *The align option will only function on open profiles or curves. Use BREAKVW 
  and JOIN3D to work around this.

OFFSETSF
 *If the offset distance exceeds the surface's radius of curvature a self 
  intersecting surface may result.

PROJECTSF
 *Selection indicates the portion of the surface that should be kept when 
  using the 'trim' option
 *When using the NORMAL option only the points that have coverage over the 
  surface will be projected. The projection will be based 
  upon the projected points, and then extended to the edges of the surface.

SWEEPSF 
 *Closed curves are not supported as input data when used in conjunction with
  multiple rails.


Known Problems
==============

 *When first opening a file after bringing up AutoCAD/AutoSurf, you are
  prompted to save changes.  This occurs because the loading of the AutoSurf
  menu signals a database change.

 *When using EXTRUDESF to extrude down a two point line, the display of the 
  line will remain highlighted after the extrusion operation has been 
  completed until a redraw is performed.

 *EDITSP and EDITSF  - When using the "Pull" option in conjunction with the
  "Cursor" option, some temporary display data may be remain if multiple
  viewports are displayed. This is easily cleaned up with a REDRAW.

 *Displaying the polyface mesh of surfaces sometimes produces a mesh that
  can cause an ARX termination when attempting to render it.  Slightly
  changing the Display Tolerance and regenerating the polyface mesh will
  in most cases correct this.

 *Displaying the polyface mesh of surfaces sometimes produces unexpected 
  results. A subsequent "SHADE" or "RENDER" may show "holes" or gaps in the 
  surface. Slightly changing the Display Tolerance and regenerating the 
  polyface mesh will in most cases correct this.

 *AME2SF - This bonus command may produce incorrect results when the BFile
  of the AME solid doesn't contain correct information (i.e. there are missing
  edges, duplicate edges, and incorrect edges etc.).


 AutoSurf Release 2.1  QUESTIONS AND ANSWERS
 ===========================================
	
Q. Sometimes when I project lines onto cylindrical surfaces (or any surfaces 
   that span a completely closed shape), the projection or automatic trim 
   option will fail, why?

A. What is happening is that you are attempting to project the data across 
   the "start/stop" boundaries of the surface. In other words, remember that 
   all slab surfaces (with one exception of a blended or corner fillet), have 
   four sides to them. When you make a closed surface (like a cylinder), 
   somewhere on that surface there is a "seam" where the "start edge" lies on 
   top of the "finish edge" of the surface.  The initial AutoSurf Release 2.1 does 
   not handle situations where you attempt to project entities that span 
   across these "seams", correctly. The solution to these cases is to either
   1) break your data at the "seam" and project/trim each side separately
   or 2) rotate the cylindrical surface so that the lines you project no longer
   cross the seam.

Q. Sometimes when I create a "cylinder type" of surface (not an actual 
   Primitive Cylinder), flow lines and other surface outputs come out 
   "all over the place" instead of consistent, why?

A. Let's use an example to explain this. Suppose you have 3 Circles, all 
   parallel to each other and a few inches apart.  You would expect that if 
   you create a loft surface by picking all three, that you would get a nice 
   cylinder shape, and in fact you will, as long as the 3 circles all start at 
   the same relative place. Picture that you're looking straight down at the 
   3 circles so they appear as one. A Circle has a "Start" and "end". If all 
   three circles all start and end at 12 o'clock (or whatever - all the same), 
   you will get a nice uniform surface with a "start/end" seam that is 
   parallel to the shape of the cylinder. Flow lines (which "flow" 
   proportionally between surface edges), will also be nicely parallel to the 
   cylinder's shape.

   But if the "start/end" points of each Circle are different (perhaps at 
   12:00, 4:00, and 8:00), you will get a cylindrical surface with a 
   diagonal seam, then any flow lines made from it will be spiral shaped 
   around the cylinder. Surfaces are developed (internally) by taking the 
   input data and mapping it out to a "Parametric square" world where there is 
   a "Top" , "Bottom", "Left", and "Right" edge to the "parametric surface".  
   The more consistent the input data is, the better surface it can be mapped 
   out to. For example, picture how the 1st cylinder example (parallel seam) 
   would "unwrap". If you could lay it on the floor, break it at the seam and 
   unroll it out till it was flat, you would have a perfect rectangle, which 
   nicely maps out to a perfect internal parametric square.

   But if you try to unwrap the cylinder with the diagonally shaped seam, it 
   will roll flat into a parallelogram, it will not map as well to the 
   internal parametric square, and the flow lines will be diagonal. For all 
   surfacing, the more consistent the input data, the more uniform the
   resulting surface. 
 
Q. How do I control my surface display so that I don't have what looks like 
   a faceted surface? 

A. The display of surfaces and splines can be controlled by setting the system
   variable ASSURFDISP. You also have the ability to have a tight creation
   tolerance (ASSYSTOL), and a loose display tolerance for highly accurate
   modeling with quick redraws.
   
Q. How can I use the AutoCAD 'hide' command to view my 3d surfaced parts?  

A. Using the AutoSurf command 'DISPSF', you can select which surfaces 
   you wish to view, then choose the polyface mesh unhide option.  Now your 
   surface has the polyface mesh turned on and you can use the 'hide' command 
   to view your part.

Q. How can I turn off my surface normal?  

A. A surface is like a quilt, made up of a collection of patches. Simple surfaces
   may only have one patch, while complex surfaces will have more patches. When 
   you use the AutoSurf 'DISPSF' command you have the option of showing all 
   normals. This will generate the normals of each patch on the surface at 
   their U-V 0,0 location. These are drawn as a temporary display entity, and 
   a redraw will remove them.  The surface normal that is always there is the 
   normal for the whole surface, all the patches combined into 1. This normal 
   cannot be turned off. It can however, be set to a very small length 
   (0.0001).  If you are trying to plot your model, and that small of a normal 
   is unacceptable to you, then an alternate surface display can be obtained 
   with the AutoSurf 'profsf' command.  This command creates a profile of your
   surface, and will change the color of hidden lines for an added ease of visibility.

Q. Will AutoCAD's shading and rendering capabilities be applicable to 
   AutoSurf surfaces? 

A. Yes.  Using the AutoSurf command 'DISPSF', you can unhide a surface's 
   polyface mesh, thereby making it recognizable for rendering and shading 
   purposes.

Q. How can I tell the difference between my U and V lines on my surfaces? 

A. The default number of U and V lines is set to 5 by 3. Simply count
   the number you have. You can change this by setting the system variables 
   ASSURFU and ASSURFV to any value you may want.  Also in the 'DISPSF' 
   command there is the option of showing you which lines are which by using 
   the 'Show U Direction' and 'Show V Direction' option, which may be helpful 
   if you are zoomed in close on a surface.

Q. How can I change the tolerance of the polyface mesh? 

A. The tolerance of the polyface mesh is controlled by the system variable 
   ASSURFDISP, which is the display tolerance. We recommend leaving the 
   surface display tolerance set to its default value, and only changing 
   it when needed for a particular surface.  While in the 'DISPSF' dialog 
   box, click on the polyface mesh unhide box, and the display tolerance 
   box. Change the display tolerance to suit your needs. Changing the 
   display tolerance here will only affect the surfaces you have selected.

Q. How will the system tolerance affect my metric drawings?  

A. AutoCAD by default has no units. However, the default AutoCAD 
   drawing is a 12 by 9 drawing.  This has to be interpreted as an English 
   system of units. Therefore AutoSurf's system tolerances have all been 
   scaled to reflect an English system of measurement.  If you are going to be 
   working in a metric environment, we recommend scaling your tolerances to 
   also reflect metric units. As you can imagine a thousandth of an inch is a 
   workable unit, but a thousandth of a millimeter is very small.  At the very 
   least you will need to scale your system tolerance (ASSYSTOL) and your 
   display tolerance (ASSURFDISP). If not your drawing file could become very 
   large byte wise, and be very slow and cumbersome to work on.
