This archive contains version 4.51 of GemCad, a computer aided design program to assist in designing faceted gem cuts. This file is meant to introduce the program, give version details, and give installation instructions. GemCad simulates a faceting machine. You can specify angles and indexes, and GemCad will cut facets on the screen, drawing the stone at each stage. This is valuable for checking the validity of published faceting diagrams. Although GemCad simulates a faceting machine, its real purpose is to do the "grunt work" of designing new gem cuts. GemCad can figure the angle of a facet given two points and its index, and it can figure the angle and index given three points. GemCad understands radial and mirror-image symmetry. If you tell it to cut one facet, it will automatically cut the other facets on the tier. GemCad can scale a stone, adjusting the angles for different indexes of refraction. GemCad can stretch a round design into an elliptical one. GemCad can produce formatted listings suitable for use as faceting diagrams. GemCad can trace rays of light through the stone to help you find out where light leaks out the pavilion. See the HTML version of the GemCad manual for detailed instructions. GemCad is an old DOS program but will run in a DOS box under Windows 3.1, 95, and 98. With modern machines you will run GemCad in either VGA 640 by 480 resolution or Super VGA 800 by 600. Not all graphics hardware is supported at this resolution. You will have to try it and see if it works on your system. To install the program onto your hard disk, I recommend making a subdirectory (folder) called GEMCAD on your hard disk and then copying all of the files to that directory. If your hard drive is C: and your floppy is A:, do the following at the DOS prompt: C: CD \ MD GEMCAD CD GEMCAD COPY A:. You can also do the equivalent from the Windows Explorer. If you run GemCad from the DOS prompt, it is not important where the executable GEMCAD.EXE goes so long as the directory where it resides is in your PATH (see the PATH command in your DOS book). For example if you put GEMCAD.EXE in a directory called C:\GEMCAD, you should make sure that C:\GEMCAD is included in the PATH statement: PATH=C:\WINDOWS;C:\WINDOWS\COMMAND;C:\GEMCAD in your AUTOEXEC.BAT file. (Your PATH statement might also have entries for other packages you have already installed. Just make sure all of the entries are separated by semocolons.) You can use Windows Notepad to edit your AUTOEXEC.BAT file. To run GemCad, type GEMCAD at the DOS prompt or click the shortcut if you have created one. There are three ways to "drive" GemCad. The first is with the function keys, legends for which appear at the left of the screen. Legends beginning with ">" change to a new menu of functions. The second way is with the mouse; you can point at a function key label with the mouse and click a mouse button to activate it. The third way is with the standard alphabetic keys. The single letter at the right of the function key labels is equivalent to the corresponding function key. The h (help) key (or function key F11) followed by another function key or alphabetic key will print a short description of what that command does (without actually performing the command). You can print the text file QUICKREF.TXT to make one-page quick reference. It shows the the single keystroke commands and a short description of what each does. You can also print MENU.TXT if you want an overview of the menus. The files in this archive include: README.TXT This file GEMCAD.EXE GemCad program QUICKREF.TXT Quick Reference for GemCad MENUS.TXT All of the menus on one page Also included are several sample cuts that I designed or adapted. These can be read in with the Open command in the File menu. TRIBBLE.GEM Tribble, a triangular brilliant, for quartz. OBRIL45.GEM 4:5 oval brilliant for quartz. On manual cover. FORMEE_R.GEM Rectangle for quartz. PEND7Q.GEM Brilliant Pendeloque for quartz. Listings of cutting instructions for each of these designs are provided in the following files: TRIBBLE.LST OBRIL45.LST FORMEE_R.LST PEND7Q.LST GemCad is Copyright (c) 1990-1993 by Robert Strickland. I reserve all rights to the program. Since January, 2001, GemCad is free and may be freely redistrubed. It may not be sold, and all redistributions must include this README.TXT file. Redistributions must also include the HTML version of the GemCad manual or a link thereto. GemCad is distributed without warranty of any kind. I am not liable for any loss of or damage of data on your computer when using GemCad. I can accept no responsibility for the accuracy of the designs you produce with GemCad, nor can I be liable for damage to a stone cut with design produced with GemCad. If you discover a bug in the program and can isolate it, please notify me, and I will gladly fix the bug, but you must still pay the $10 update fee to receive an update with the bug fix. My raytracing program, GemRay 1.5, uses raytracing to make a picture of the finished stone. It evaluates the optical performance of the design under several different lighting conditions. GemRay needs an 80x87 math coprocessor to run at reasonable speed. GemRay requires a VGA card and monochrome or color VGA monitor. The fee for GemRay is $50 for registered GemCad users. GemRay also comes with a program called GemFlick that plays back a series of frames made by GemRay, making an animated movie of a stone as it tilts. GemRay also comes with GemFrame, a utilty to run GemRay once for each tilt angle. GemFrame also can tangent-ratio scale a design, allowing you to scan for the best angles. Robert W. Strickland 6408 Earlyway Dr. Austin, TX 78749-1632 *********************************************************************** KNOWN BUGS IN 4.51 FUNCTION KEYS If your keyboard does not have F11 or F12, or if your F11 or F12 keys do nothing, you may use Shift-F1 or Shift-F2 instead. This was not in the first printing of the 4.0 manual. VOLUME The volume of the stone shown with the l or L (list to screen or file) commands (version 3.3 or later) is dependent on the actual thickness of the girdle you have cut as it appears on the screen. Thus, if you cut the design twice with two different girdle thicknesses, the volumes will be slightly different. The height of the stone given by the list command as H/W=P/W+C/W+0.02 assumes a 2% girdle. When computing the volume, GemCad does NOT assume a 2% girdle but uses the thickness as it appears on the screen. WRITE COMMAND The Write (W) command makes very compact ASCII files of designs. The write command lists pavilion facets are with negative angles and crown indexing. The Read (R) command has no problem flipping the indexes around, so files written can be read in again. A human might not be able to cope as well, however. Therefore, do not use the .ASC files as cutting instructions. Use the List (L) command. *********************************************************************** CHANGES 4.5 to 4.51, August 3, 1993 WON'T SAVE Version 4.5 had a bug in which sometimes it would refuse to save a file using the save command. It would ask you for permission to overwrite the file but then would not actually save the file. When you quit it would warn you that the file had not been saved. This has been fixed in 4.51. *********************************************************************** CHANGES 4.43 to 4.5, June 9, 1993 NEAREST NOTCH When you scale the stone with the Scale (X) command in the X or Y directions there is no guarantee that the indices will be whole numbers. This happens when you stretch a round design into an oval. After scaling the stone Version 4.5 will now ask you if you want it to TRY to round off the indices to the nearest notches. If you answer yes, GemCad will search through the following index gears: 64, 72, 80, 96, and 120. It will sort them in order from best to worst. The "best" gear is the one that makes the indices come out to be nearest to whole numbers (nearest in angle, that is). GemCad will then ask you for the index gear. If you just press Enter, GemCad will use the first gear in the list. If you want a different gear (even if it is not in the list) just type it in here. It will then proceed to try to round off the indices. The algorithm GemCad uses is an iterative one. It will redraw the stone several times. You will see the meet points move and the facets change shape as GemCad tries to round off the indices. After this process, you might have to use the Change (C) command to make the facets meet up again, particularly with the gears with fewer numbers of teeth. If you don't have a math coprocessor, this process will be very slow! You can press the Escape key to interrupt the process if it is taking too long or changing the shape too much. The iterative process will occasionally diverge on narrow stones or stones that have facets too close together in index. If this happens, it will print an error message and then undo the scaling. The smaller the number of teeth on the gear and the closer in index the facets are, the more trouble GemCad will have. The L/W ratio might be slightly different than what you asked for. After the nearest-notches process, GemCad will retier the stone and automaticlly figure out the new symmetry. RETIER After retiering the stone (when you use the X or Y options of the Scale (X) or center (c) commands), previous versions would ask you for the symmetry. Now, GemCad checks the design and resets the symmetry to 1, 1-y, or 2-y, whichever is appropriate. CHANGE COMMAND The Change (C) command takes the index of the facet surrounding the cursor, rounds it off to the nearest whole number, enters it as if you typed it in with the index (i) command, and then kills it. You can then enter an angle and a point or two points to recut the facet. But sometimes you want to change the index of a facet. Previous versions of GemCad would make you type in the new index after using the Change command. This led to difficulties if you wanted to preserve two meet points, because GemCad would immediately recut the facet without letting you enter the new index. To solve this problem, in version 4.5, if you have already entered in index with the index (i) or jam index (j) commands before using the Change command, GemCad will keep the index already entered. BYSECT COMMAND The Join (J) command added in 4.42 has been renamed bYsect (Y). Either Y or J work in 4.5, but the J will be dropped in the future. The bYsect (Y) command allows you to bisect a line segment to interpolate between the last two previously set points (regardless of whether they were used to add a new facet). The main use is to set a point along an existing edge at a precise distance between two existing meet points. Say you want a new set of facets to meet along an existing edge a third of the way between two existing meet points. Set the first and then second meet points with the meet point (m) command (but don't enter y to use the points). Next, press the bYsect (Y) key. GemCad will prompt you for the fractional distance between the points. It wants a number between zero and one. Entering zero gives you the first point and entering one gives you the second. Entering 0.3333333 gives you a third of the way from the first to the second. The bYsect command is now in the Point Menu. It displaces the Undo command in the Point Menu of previous versions. SUPER VGA GemCad now supports Super VGA cards in the 800 X 600 screen resolution. Unfortunately the software package I am using cannot automatically detect the presence of this hardware. You can get this resolution by reconfiguring GemCad by typing c at the first prompt and selecting s for the graphics adapter when that question comes around. (You should be in the directory where GEMCAD.EXE resides when you do this, or the configuration will only apply to when you run GemCad from the current directory.) You can also type GEMCAD S from DOS. This will override whatever is set by the configuration file. ASPECT RATIO If you have a laptop or a monitor that does not have a vertical height adjustment and your squares and circles are coming out rectangles and ellipses, GemCad allows you to adjust the aspect ratio of its display in software to compensate. To use this feature, run GemCad. Measure the width and height of the big square surrounding the four views. (A millimeter ruler is most convenient for this.) If the width and height are not identical, divide the height by the width and write down the result. Next, exit GemCad and get back to DOS. Run GemCad again, enter the configuration section of the program and set the screen aspect ratio to the number you calculated. Now repeat the measurement process. The width and height should now be a lot closer. If not identical, you can fiddle with the number to make it come out right on. Previously, the screen aspect ratio was controlled by a DOS environment variable called ASPRAT (see 4.0 to 4.1 changes below). If you have such an environment variable, it will override what is set in the configuration file. ALIGNMENT There is a new command to help you make lines that are exactly horizontal or vertical (parallel to the top or side of the screen). The command is a lower-case t. I call it "tack." It replaces the obsolete timelapse command. For now, it is in the Utility Menu. (It would be more convenient if it were in the Point Menu, but I ran out of room.) The tack command does nothing by itself but is actually an alignment tool, sort of a straight edge, for the point on facet (f) command. It has the effect of tacking down one of the coordinates of the cursor to the previous point. Let's say you want to cut a new facet so that the the edge between the new facet and an existing facet is exactly horizontal in the Top View. Futhermore, let's say that you want the new facet to meet an existing meet point. First, use the meet point (m) command to pick the first meet point. Next, press the t key to "tack down" the cursor. (You'll see a message in the information box in the upper lefthand corner of your screen saying that the tack feature has been turned on.) Then move the pointer horizontally to the interior of the adjacent facet. Then when you press the point on facet (f) key to set the point, the cursor will jump so that is exactly level with the previous meet point. Finally, enter the index of the new facet, and GemCad will cut it so the new edge is exactly horizontal. Before, the best you could do was to line up the points visually with the aid of the crosshairs. You can use the same process to make vertical lines. GemCad will check if the two points align more nearly horizontally or vertically in the current view to decide which direction to move the new second point. The tack command will work in any of the four views, but you need to make sure that the points you are aligning are both in the same view. The tack command applies only to the point on facet (f) command and not to any of the other point commands. The existing point that the new point on facet is aligned with can be set with any of the point commands, however. The point that the alignment is keyed to need not be actually used to cut a facet; it can be dismissed by answering no to the question about whether to use the point. If you press the tack key by mistake, press it again to untack. PAGE UP/DN The Page Up, Page Down, Home, and End keys now work as expected in the file picker when there are more than one screenfull of file names. This applies to the open (O), read rext (R), and import (M) commands. This makes it much easier to navigate through direc- tories containing hundreds of designs. *********************************************************************** CHANGES 4.42 to 4.43, September 28, 1992 DUP. NAMES If you give two facets on the same tier different names (with the name (n) command), GemCad will issue an error message on the list (l) and List to file (L) commands. *********************************************************************** CHANGES 4.41 to 4.42, September 28, 1992 JOIN COMMAND This was the predecessor to the bYsect (Y) command above in 4.5. The join (J) command doesn't yet show up in the Point Menu or with the help command. I have run out of room in the Point Menu, so I'll probably displace the undo command in the Point Menu. This will be done in version 4.5. [It was.] The remaining unused alphabetic keys are o, U, and Y. If anyone figures out a better name than "join" beginning with one of these letters, let me know. (Other candidates are Ynterpoate, interpOlate, or bYsect.) [I decided on Y for bYsect for version 4.5] MORE DIGITS If you set the same point two or more times in suc- cession, GemCad will print out its coordinates to seven place ac- curacy. Likewise, if you use the blink (b) command two or more times in succession on the same facet, GemCad will print out the angle and index with higher accuracy. *********************************************************************** CHANGES 4.4 to 4.41, September 14, 1992 GIRDLE INDEX In versions up to 4.4, girdle facets were sometimes listed with the wrong index. Sometimes some girdle facets were omitted and others were repeated in the listing. This has been fixed in version 4.41. The version 4.4 READ.ME file erroneously reported this bug as fixed. GIRDLE FACETS In versions prior to 4.41, girdle facets were listed with the wrong indexes when all of the following three conditions were met: 1) The girdle outline is not symmetrical about the line through the zero index notch (it is not mirror-image symmetrical). 2) The crown is cut before the pavilion. 3) The girdle facets are cut before transfering to the pavilion. If these conditions were met, the List to File (L) and List to Screen (l) commands would list girdle facets with pavilion indexing even though they were listed with the crown. GemCad 4.41 now lists the girdle facets with indexing according to whether the previous non-girdle facet was a pavilion or crown facet. It considers all facets between 89.5 and 90.5 (-89.5) degrees to be girdle facets and lists all such facets as 90.00 degrees. If the girdles are first in the listing, GemCad searches for the first non-girdle facet and uses pavilion or crown indexing accordingly. If all of the facets are girdle facets, GemCad uses crown indexing and uses the heading "PREFORM." FILE NAME BOX There is now a file name box just above the status box in the lower-lefthand corner. It will contain the name of the file read in by the Open command. After the design is modified, you will see the word MOD after the file name. You will also the word NEW after the file name when you first run GemCad or use the New (N) command to start a new design. If you have not yet saved a new design the file name will be shown as "(UNTITLED)." If you read in an ASCII file with the Read (R) command or import a Long & Steele file with the import (M) command, GemCad will delete the extension from the file name and put it in the file name box with the word NEW after it. If you then use the save (s) command to save the file, you will save the file as a binary file with the same base name but with the .GEM extension. Using this feature, you can quickly translate from the two other formats to GemCad binary files without typing in file names. NAME The name (n) command now allows you to edit the pre- vious name of the facet. Thus, if you accidently press the n key inside a facet that already has a name, you can just press Esc or Enter, and the name will remain unchanged. Now, if you want to delete a previous name you now have to backspace over it. WRITE COMMAND The write (W) command to make compact ASCII files had a couple of problems. The most serious was in designs with a zero degree facet in the pavilion (culet facet). GemCad would place the pavilion zero degree facet in the crown when the design was read back in with the read (R) command. The supposed-to-be culet would then either miss the stone or cut off the table. You can patch existing ASCII files by negating the radius (the second parameter after the angle). The second problem was that the write command would each girdle facet on a separate line. This would result in files that were bigger than they should have been, but would read back in OK. When archiving files with the write (W) command, always check to make sure the read (R) command can successfully read back in the design. *********************************************************************** CHANGES 4.3 to 4.4, August 31, 1992 WRITE COMMAND GemCad would sometimes crash with a floating point error when writing an ASCII file with the Write (W) command. This would happen on girdle facets in 4.3. ESC KEY When at the command level, the escape key is no longer equivalent to the Quit (Q) command. PRINT SCREEN With IBM or Epson printers, you were supposed to be able to configure GemCad to do a screen dump directly to the printer by configuring it not to ask you for a file name each time and by entering PRN for the default file name. There was a bug in versions 4.0 to 4.3 that caused the error message "Cannot open" to be printed out every time a screen dump was attempted. The work-around for this bug was to configure GemCad to ask you for a file name each time and enter PRN for the file name for each screen dump. This bug has been fixed in version 4.4. *********************************************************************** CHANGES 4.2 to 4.3, August 6, 1992 NEAREST NOTCH GemCad allows you to cut a facet on a girdle outline by setting two points with the (p) command) and entering an angle of 90 degrees. GemCad will figure the index and cut the facet. In version 4.3 and higher, GemCad will first round the index to the nearest notch (whole number index) before cutting the facet. Formerly, you had to use the change (C) command to make these facets have whole number indexes. ANGLE CHECK It is difficult to cut a pair of adjacent facets at nearly the same angle and index accurately. Small errors in cutting can change meet points drastically, and what you usually get is a single rounded facet instead of two flat ones. Now, the playback (P) command will check the angle between every pair of facets and report all facets less than 5 degrees apart. The two facets will be highlighted, and the angle between the facets will be printed at the top of the screen. The angle reported is the dihedral angle at the edge of the two facets and not just the difference in bearing angle between the facets. This check is performed after the stone is completely recut. If there are no facets close together in angle, then no error messages will be printed. *********************************************************************** CHANGES 4.1 to 4.2, July 15, 1992 SYMMETRY In versions since 3.92, if the index gear is not an integer multiple of the degree of radial symmetry, GemCad will round off the index to the nearest tooth when reflecting a facet by symmetry. This allows you to make five-sided designs on a 96 index gear with integer indexing, for instance. There was a bug in versions 3.92-4.1. If you picked the clockwise orientation of index gear (negative number of teeth), GemCad would sometimes hang when cutting facets if the degree of radial symmetry was not a divisor of the number of teeth on the gear. This has been fixed in 4.2. GIRDLE FACETS The girdle facets are no longer affected by tangent- ratio scaling. WRITE The write command of previous versions would sometimes mistakenly group together facets that were cut at ALMOST the same angle and depth AUTOSCALE On the a (all) option of the X (scale) command to scale the entire stone, when GemCad asks you for the numerator of the scale factor, if you enter zero, GemCad will scale the stone such that the largest distance from the dop axis is 1.1. To use this feature, use the X (scale) command, enter a for all, and enter 0. CENTER The center (c) command will retier the stone if you center the x or y axes. If the stone is translated a large distance such that it extends past the borders of the screen, it is made smaller so that it fits again. *********************************************************************** CHANGES 4.0 to 4.1, July 6, 1992 CENTER The center (c) command has been changed to allow you to enter a point about which to center the view. To use this new feature, set a point with any of the point commands BEFORE using the center command and enter yes to use the point. You should see 1pt in the status box in the lower-lefthand corner of the display. Then, use the center command. GemCad will use the previously set point instead of the location of the cursor. If no points have been set, the center (c) command uses the location of the cursor just as before (as docu- mented in the manual). PRINT SCREEN The Print Screen (F12 or Shift-F2) command will now work in the middle of a playback (P). If you answer yes to the question about waiting for a keypress between facets, GemCad will prompt you with the "Next facet " message between facets. You can now use the Print Screen command here to print out the design. GemCad will clear the message, print the screen and then cut the next facet. ASPECT RATIO If you have a laptop or a monitor that does not have a vertical height adjustment and your squares and circles are coming out rectangles and ellipses, GemCad now allows you to adjust the aspect ratio of its display in software to compensate. To use this feature, run GemCad. Measure the width and height of the big square sur- rounding the four views. (A millimeter ruler is most convenient for this.) If the width and height are not identical, divide the height by the width and write down the result. Next, exit GemCad and get back to DOS. Set the environment variable ASPRAT to the number. Let's say you the ratio was 0.92. Enter the following line at the DOS prompt. SET ASPRAT=0.92 Now, run GemCad again and repeat the measurement process. The width and height should now be a lot closer. If not identical, you can fiddle with the number to make it come out right on. It's best to put this command in your AUTOEXEC.BAT file. If you ever get the error message "Out of environment space" give me a call, and I'll tell you how to increase the environment variable. RETIER The scale (X) command retiers the stone if you scale the X or Y axes for instance to turn a round design into an oval. This means, it groups together facets that are cut at the same bearing angle and mast height. Previous versions of GemCad would corrupt the design if was very complicated with a large number of tiers. *********************************************************************** CHANGES 3.96 TO 4.0, May 21, 1992 MANUAL New manual for 4.0. FOOTNOTE Added the footnote (F) command to allow you to enter up to four lines of text that shows up at the bottom of the listing with the l or L commands. READ/WRITE I completely changed the format of the ASCII files written with the Write (W) and read by the Read (R) command. Now the index of each facet is incuded in the file, so the bug in previous versions pertaining to changes in symmetry is fixed. GemCad 4.0 can no longer read ASCII files written with the W command from by previous versions. (It can however open with the Open command (O) any binary file made by any previous version with the save command.) CONFIGURATION GemCad will now ask you to type c to enter a configuration mode. This allows you to set default index gear, symmetry, refractive index, page layout for the List (L) command, and printer choices for the screen print. This is saved in a file called GEMCAD.CFG in the current directory. When GemCad is first run, it looks for this file first in the current directory, and if not found there, it looks in the directory where the executable GEMCAD.EXE resides. *********************************************************************** CHANGES 3.81 TO 3.9, October 22, 1991 BOTTOM LABELS In version 3.8 and maybe in 3.7, facet labels in the Bottom View were invisible. 3.91 12/17/91 Might have fixed the "mousy bug" above. 3.92 2/2/92 Cut off facets handled much better. Playback command now allows pause between facets. List commands now make separate indices with hyphens instead of spaces. If the degree of radial symmetry is not an integer divisor of the number of teeth on the index gear, indices will be rounded off to the nearest tooth. 3.93 2/25/92 Names are now better positioned inside facets, particu- larly in long skinny triangular facets. Made file picker optional. GemCad will ask the file name as version 3.5 or before. If you respond with just the Enter key or escape, GemCad will display all of the design files with the .g?? extention. Press Escape to exit the file picker without picking a file. 3.94 4/15/92 Added the G (Gloss) command to allow the user to annotate the listing with cutting instructions. A gloss is an annotation or short explanation. To enter the cutting instructions for a tier of facets, place the cursor inside any of the facets of that tier and press G. GemCad will prompt you for the cutting instructions. Cutting instructions will show up on the listing with the l and L (list to screen and list to file) commands. Only one note per tier will show up on the listing. If the facet already has cutting instructions, GemCad will allow you to change them. The cursor keys and the Insert, Delete, Home, and End keys now work as expected. Files made version 3.94 that have cutting instructions cannot be read by prior versions, but all previous files can be read by 3.94. 3.95 4/21/92 Fixed bug in new G command 3.96 5/8/92 Added H (Heading) command to allow you to enter title, designer, date, etc. The heading can be up to four lines long. The heading shows up at the top of the listings made with the l (list to screen) or L (list to file) commands. I made allowances for non-integer index gear offset (the number that appears at the bottom of the index gear wheel). This is so you can put the ID position at the top with gears with odd-numbers of teeth. I completely reorganized the menus. All commands are now executable from the menus. The function key numbers in the 3.0 manual no longer correspond to version 3.96. See the file MENUS.TXT or the printout on the back of the quick reference sheet. Also, if you use the spacebar to make the full-screen crosshairs, the mouse position will be "frozen" at the crosshairs, and a menu selection that requires a point will take the location of the crosshairs. Files written with 3.96 cannot be read with prior versions (or with GemJet, GemDot, or GemPlot versions less than 1.7), but all previous files can be read by 3.96. I changed the routine that labels facets. Sometimes, a facet of high angle would not be labeled in any view. Now all facets are labeled in the top or bottom views. This applies to GemJet, GemDot, and GemPlot 1.7. *********************************************************************** CHANGES 3.7 TO 3.8, August 26, 1991 FILE PICKER The file picker introduced in version 3.7 (see below) now works with the M (iMport) command to import Long & Steele files. By default, it displays the files ending with the .?3D extension. 3.81 9/25/91: highlighted file is also indicated with a pointer for some obscure graphics adapters that don't support highlighting. *********************************************************************** CHANGES 3.5 TO 3.7, July 27, 1991 (3.6 was a dud) SCREEN DUMP Prior versions of GemCad had problems doing a screen dump to certain IBM ProPrinter compatibles (a genuine 9-pin ProPrinter and the Tandy DMP 134 in particular). The symptom this problem was that the printer would only print one row of graphics corresponding to the top of the screen and then just advance the paper instead of printing the rest. GemCad now puts both carriage return and linefeed characters at the end of each line of graphics instead of just a linefeed. This will make the screen dump work with a greater range of printers. FILE PICKER No more typing file names to open an existing project! The O (Open) command now brings up a ``point and shoot'' file picker. GemCad will display all of the files in the current directory that end with an extension matching *.G* (that is, files whose extensions start with G). The names of any subdirectories will be also be shown and can be distinguished by the trailing backslash \ character. One of the entries will be lit up. You can change which entry is highlighted with the cursor keys or the mouse. Pressing the Enter key or either mouse button causes the highlighted entry to be selected and the project to be opened. If the highlighted entry is a directory (if it ends with the \ character), GemCad will change to the selected directory and display all of the files matching the wildcard. The special directory named ..\ is the parent directory of the current directory. If there are more than one screenful of entries, you will notice the special selection . Selecting causes the next screenful to be displayed. The special entry will then back up one screenful. The special entry is used to change drives (A:, B:, C:, ...) and/or the wildcard (default *.G*). To Esc key escapes the file picker without making a selection and aborts the Open command. Selecting a blank area of screen also escapes. GIRDLE LABELS Gemcad now places girdle facet labels around the peri- meter of the stone outline in the Bottom view. GemJet 1.2 also does the same thing. You must still place the cursor inside the facet to be labeled in the Side or End views, but the resulting label will be placed in the Bottom view. GIRDLE FACETS If there are more than 64 girdle facets, the girdle outline is assumed to be rounded, and girdle facets are not drawn. The Girdle command of 3.4 and 3.5 to turn on or off the plotting of girdle facets was eliminated in favor of this automatic approach. ANGLE A new command, A (Angle) gets the angle of the facet surrounding the cursor and enters it just as if you had typed it in. The analogous function for duplicating the index of an existing facet is the j (jam) command. One use of the A command is for cutting step cuts that have several facets at the same angle but at different indexes. After you cut the first tier of a step cut, you can march around the stone grabbing the angle of the facet just cut with the A command and then moving the cursor to a facet from the previous tier and grabbing its index with the j command. Then just pick the meet point, and GemCad will cut the new facet. Z-Axis A new point command, Z, sets a point at the intersec- tion of the facet surrounding the cursor and the z (dop) axis. It is most useful when cutting several facets to a common center point, as with a CAM preform. Another use is for designs that have several facets cut at the same angle and depth but with indexes not compatible with the current symmetry (as set by the y command). You can cut one of the facets, place the cursor inside the new facet, grab its angle with the A command (above), and then grab its z-axis intercept with the Z command. Then, as soon as you enter the the index, GemCad will cut the new facet. *********************************************************************** CHANGES 3.4 TO 3.5, February 15, 1991 MEMORY GemCad version 3.5 can handle stones with a LOT more facets. Previously, a recursive routine was used to free all memory (such as with the u (undo), N (new), or Q (quit) commands). This would cause a stack overflow (but no error message) and cause your machine to hang if there were more than about 250 facets and you used one of these commands. Now, the limit is determined only by your patience and the amount of available memory in your machine. As an experiment, I cut a stone with 1200 facets with no memory problems! *********************************************************************** CHANGES 3.3 TO 3.4, February 5, 1991 VECTOR Two new commands have been added but do not yet show up as function keys. They are the v and V vector commands. A vector is something that has magnitude and direction. The purpose of the com- mands is to display the length and direction of the line joining two points. The v (vector) command prints the distance between the last two points and the bearing angle and index of the line joining them. The delta x, delta y, delta z and true distance are shown. The two points are the last two points that were set, whether or not they were used to cut new facets. By far the most usual point command to be used in this context is the m (meet) command. If you want to mea- sure the length of an edge, move the pointer near one end point of the edge, press m, enter n (we don't want to use the point to add a facet), move the pointer near the second point, press m, enter n, and press v. GemCad will then display the delta x, delta y, delta z, and true (diagonal) distance at the top of the screen. After you press enter, GemCad will then print the bearing angle and index of the line joining the two points. If the two points lie along the edge joining two facets, and if you were to try to cut a facet at the angle and index given, it would just touch the edge, and furthermore, the given angle is the smallest angle (in absolute magnitude) that could intersect the specified edge. This is useful when cutting a facet midway between a pair of existing facets--like a main between two breaks. So, in what units are the distances given? The purpose of the V (Vector set) command is to set the scale of the measuring stick used by the v command. It will start off by doing exactly the same thing as the v command, but then GemCad will ask you which of the given distances to which you want to set your measuring stick. Acceptible choices are x, y, z, or r for delta x, delta y, delta z, or delta r (diagonal distance), respectively. GemCad will then ask you how long this distance should be in the new units. The measuring capability previously provided with the construction line command has been removed. *********************************************************************** CHANGES 3.2 TO 3.3, January 20, 1991 DISK FULL The commands that write to the disk now do error checking. Previous versions would corrupt files silently if the disk filled up. Now you will get the error message, "DISK FULL? File xxx corrupt" if GemCad encounters an error writing file xxx. This change applies to the s, S, W, and L commands, as well as to the backup file gemcad.bak that GemCad uses for the u (undo) command. VOLUME The volume of the stone is now computed and displayed with the l and L (list) comands. The volume is displayed as a fraction of the cube of the width, W, of the stone. For example, Vol./W^3 = 0.279 This number can be used to estimate the carat yield of a finished cut. To do this, measure W with a caliper in centimeters (mm/10), compute W cubed (W times W times W), and multiply the result by the specific gravity of the material in g/cc times the number for Vol/W^3 given by GemCad. The result will be the estimated weight of the stone in grams. Multiply by 5 to get the weight in carats. As an exercise, let's compute the weight of a 12 mm wide stone of quartz with Vol./W^3 = 0.279. Noting that quartz has a specific gravity of 2.65 g/cc, and 12mm = 1.2cm, Weight = 1.2*1.2*1.2*2.65*0.279 = 1.28 grams * 5 = 6.39 carats If you prefer, you can use mm instead of cm if you want, but the weight will come out in milligrams. You then divide by 200 to get carats. Weight = 12*12*12*2.65*0.279 = 1280 mg / 200 = 6.39 carats See the bug report about girdle thickness above. MISSING FACETS In versions prior to 3.3, the first facet cut with no symmetry (symmetry 1-n) might not be drawn on the screen. A similar problem with a symmetry of 2-n existed where if two parallel facets were cut to start a design, neither would be visible. This has been mostly fixed. If GemCad is not drawing facets that you think you have already cut, try the d (draw) command to redraw the screen. If that doesn't work, try using the B (Blink) command to recompute and redraw adjacent facets. INDEX OFFSET The W (write) command now takes into account the index offset (the index location at the bottom of the screen). DEMO The D (demo) command is new for version 3.3. The demo command will repeatedly playback the cut until interrupted with the Escape key. It is a good way to demonstrate GemCad at a gem show. COMMAD LINE GemCad will now accept a design file name on the command line. For instance, gemcad design.gem will run gemcad and then open the file design.gem. Many DOS shells such as DOSSHELL with DOS 4.0 or the shell that comes with PC Tools can "launch" an application by clicking on the name of a data file. When configuring the shell, you can associate the gemcad.exe program with data files that end in the .gem extension. Clicking on a the name of a design file ending in .gem will then run GemCad and open the indicated design file. This can save you some typing (and a few synapses in remembering file names). MISCELANEOUS I also made numerous other small changes. The prompts that GemCad give are now a bit more descriptive of what it wants. The P (playback) command cleans up the display after the playback. I fixed a bug in the retier code (see the X scale command). *********************************************************************** CHANGES 3.1 TO 3.2, September 6, 1990 LIST TO FILE The L (list to file) command will now skip lines and indent columns for the GemJet program, the publication-quality companion program to GemCad for the HP LaserJet and DeskJet printers. The first time you use the L command, GemCad will ask you for the number of columns to indent. A value of -8 is suggested for GemJet. Most of the file will be indented 8 columns, but the header at the top will be indented more. Blank lines at the top of the file will leave room for the picture to be overlaid by GemJet. (Positive values will work as before, i.e. will not skip lines at the start of the file or indent to leave room for the picture.) The basic idea is to list the design to a file with the L command, edit the file with your favorite text editor or word processor to add cutting instructions for each tier, print the file on your HP DeskJet or LaserJet printer, reinsert the page, and then run GemJet to print the design. The result is a publication-quality diagram of your design. *********************************************************************** CHANGES 3.0 TO 3.1, August 1, 1990 COMMAND ECHO The alphanumeric key equivalent of the current command is displayed in the upper-left-hand corner. *********************************************************************** CHANGES 2.5 TO 3.0, June 29, 1990 NEW MANUAL A new version of the manual is now available and will be distributed with GemCad 3.X. TURBO C++ The source was recompiled with the new Turbo C++ 1.0 compiler (in its C mode). IBM 8514 1024x768 support was added, but has not been tested yet. This also fixed a bug (in Turbo C) where facets at index 10 were listed as index 1. RE-TIER The X (scale) command re-tiers the stone when stretched in the x or y directions. In pre-2.6 versions, this was done by seeing which facets are related by symmetry. Now, after the re-tier, all facets cut at the same bearing angle and depth will be grouped together on a tier regardless of how they are related by symmetry. This breaks the trick described starting at the last paragraph of 12 of the reference manual of March 1990 for version 2.0. (The trick was to have made each facet a separate tier.) BUG FIX The L (list to file) failed to close PRN, causing DOS to run out of files. This has been fixed. WAYTWACE Rays are now drawn in complement mode. Shooting the same ray twice will draw and then erase the ray. PRINT SCREEN A capital H in response to the question asked when the F10 (print screen) command will capture a screen image and dump it to a file in HP format. (The lower-case h dumps straight to LPT1.) To print such a file (here, named FILE) from DOS, do COPY /B FILE PRN The /B switch is because the file is a binary file and might contain the DOS 2.x end-of-file character ^Z. *********************************************************************** CHANGES 2.4 TO 2.5, May 25, 1990 LIST The L list to file now has a default margin of 8 spaces. GemCad will prompt you the first time you execute the L command for the number of columns (spaces) to indent. Pressing ENTER will set the default 8 spaces. GemCad will not ask you the next time through. *********************************************************************** MOUSE NOTES If you have a mouse and the pointer jumps more than one pixel at a time in one direction and/or seems very sluggish in the other, there are two environment variables MXDIV and MYDIV. For instance, if you type the line SET MXDIV=2 at the DOS prompt before running GemCad, gemcad will divide the ticks your mouse driver generates by two and make the mouse more sensitive in the X direction. The number should be a small integer like 2 or 3. If you make it too big, your arm might be too short or your desk top might be too small to allow you to move the pointer across the screen. If you enter the above command and DOS reports the error message "Out of environment space," you need to put the command near the top of your autoexec.bat file and reboot or use the /E switch on the SHELL= command in your config.sys file to increase your environment space. See your DOS manual for details on the SHELL= command. *********************************************************************** ACKNOWLEDGMENTS I wish to express my gratitude to Walter Carss for his encouragement and suggestions. Most of the features added in the upgrade from 1.0 to 2.0 were Walt's ideas. Walt deserves credit for helping to introduce GemCad to the faceting community. I thank Robert Long for his suggestions, for pinning down several bugs, for his suggestions about the import/export facility from/to his and Norman Steele's programs, for introducing GemCad to many others. I wish to thank Long & Steele for their many contributions to the art and science of gemstone design. Thanks to both for publicizing GemCad in the "Seattle Facetor Design." I thank Jerry Wycoff of the American Society of Gemcutters for his very favorable review of GemCad in the "Gemcutter." I thank Phil Stonebrook for encouraging me to add the print screen command, helping me test it, for helping me squash a bug, and for in- troducing GemCad to the American Society of Gemcutters. I thank Greg Thompson for his suggestions for improvements to the Manual. Thanks to everyone for bug reports and suggestions for new features. ***********************************************************************