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A beginning word of caution: I am not the expert. This discussion is meant to allow you to ask better questions than I did when I first started. By the time you read this, what little I do know may be hopelessly out of date. OK! Check out some AutoCAD resources on the net.
Any discussion of minimum requirements must start with the release of AutoCAD that you intend to use. Release 2000 for Windows requires a great deal more computer horsepower than Release 12 for DOS. Also, how much three-drafting do you plan to do? Three-dimension modeling and rendering requires a great deal more horsepower than two-dimensional drafting. The heart of the machine is the 'Central Processing Unit' or CPU, the chip that does the thinking.
Current state of the art is the Pentium III. I run well with an AMD 300 MHz K-6 at home and a 450 MHz Pentium II at the office. Both chips are stable and reliable. Speed is important. CAD drafting programs in general and AutoCAD in particular are large programs, running large graphics files and doing a lot of mathematical calculation. If the computer is slow to update, drafting becomes painful. Continual slow downs of one or two seconds seriously affects the pace at which you draft. Just think in terms of someone who hesitates repeatedly while speaking. Stretch those hesitations out to five or ten seconds and the results are beyond annoying.
The speed of the system bus (the traffic control system) is also important. Data passing back and forth between drives, printers and plotters, modems and other peripherals, and the CPU all travel on the system bus. Older PCI buses are relatively slow and don't expand well compared to SCSI and USB buses. Be aware that a SCSI hard drive is faster than a IDE or EIDE hard drive, but requires a SCSI bus or a SCSI adapter board. The current best bet in PC buses is the Universal Serial Bus (USB), which is fast, allows USB devices to be added or removed while the computer is running and eliminates a lot of common hardware fiddle-faddle.
PC processor and data bus clock-time is measured in MegaHertz (MHz) and is the most important measure of system speed. It is possible to do small scale two-dimensional drafting with a computer running at 100 MHz, but drafting large files and three-dimensional modeling requires 300 MHz or faster. The basic rule of thumb is get as much computer processing power as you can afford. Upgrade the rest later. On the other hand, a lighting designer may never need to draft in three dimensions or handle large files.
Speed is MegaHertz. Not enough MegaHertz hurts!
CADvise:
Memory is measured in Megabytes and again the more the better. There are two critical memory measurements: Random Access Memory (RAM) and the hard drive. RAM is the active memory that the processor uses while its working. RAM is fast (some is faster than others) and volatile. When the computer shuts down, all memory in RAM is lost. The hard drive(s) is the main storage for all the information on the computer. As mentioned above, AutoCAD is a big program with big files, so AutoCAD requires big memory. The operating system, Windows, takes up more RAM. If you open multiple files, or other programs concurrently with AutoCAD (a word processor, spread sheet, or graphics program), that takes memory. When the memory runs out on the motherboard, AutoCAD pages the information to the disk or hard drive. Everything slo-o-o-o-o-o-o-o-ws do-o-o-o-o-o-o-o-wn.
Autodesk suggested a minimum of 16 Megabytes of RAM for AutoCAD Release 11 for Windows, 32 Megabytes for Release 12 and 64 Megabytes or more for Release 13. Well, you guessed it, get 128 Megabytes or more of RAM for release 14 or AutoCAD2000. I currently use 256MB of RAM at the office, and it's not too much. Each release of AutoCAD is larger requiring more room for the program. As more information is added to the drawing file, file size is increasing. When AutoCAD processes a file it uses substantially more memory than the actual file size itself, most particullarly when doing 3d rendering. Windows multitasking encourages the drafter to open other applications concurrent with AutoCAD. For each of these reasons, the more RAM the better.
You've probably caught on by now, the hard drive or multiple hard drives need to be big and fast. When talking of hard drives we now suggest GigaBytes (that's hundreds of millions of bytes) as a starting point. More on hard drives later. See: Storage.
Memory is MegaBytes. Not enough MegaBytes bites!
Several companies sell PC's with the CAD drafter in mind. Many of these machines come fully loaded with large hard drives, graphics cards and quality monitors. Thumb through the advertisements in an AutoCAD magazine such as CADalyst, CADENCE or CADVANCE. There are also many AutoCAD user groups, which can provide advice and help. If you are a Macintosh user and prefer to stay that way, which I cannot recommend, look at the high end Macs only. Gauge yourself by the discussion on RAM and processor speeds for the PC. Talk to an AutoCAD dealer. Autodesk no longer supports the Mac, so Mac users do not have a recent release available to them, but there are other CAD packages available to them.
Your display screen should be a larger non-interlaced high resolution monitor. Get a 19" or 21" monitor. Size is measured diagonally across the face of the picture tube. The actual screen will be slightly smaller. A 15" monitor will display drawing details very small. This forces you to zoom in and out very often. You are going to stare at the screen for long periods, so the image must be crisp and rock solid. Take a long look at the screen, preferably with a CAD image displayed, or at least an image that shows colored lines on a black background. A monitor suitable for game playing and word processing is not necessarily suitable for drafting. Good drafting monitors have very rich blacks.
The technical details to be aware of are: dot pitch, interlace, and vertical refresh rate. Vertical refresh rate refers to the number of times the picture is repainted on the screen in a second. Anything less than 60 Hz will not be acceptable. The video display should be able to match your graphics cards higher output. If the graphics card produces a display at 60 Hz, 72 Hz and 76 Hz, get at least a 72 Hz monitor. The increase to 76 Hz will be minimal.
Broadcast television is interlaced, meaning that each picture is made of two "interlaced" side-by-side passes of video which blend on the screen. Interlaced pictures are for television, not computors. Try sitting four feet from your television for a half hour. Non-interlaced monitors are much crisper and have less flicker, making them much easier on the eyes.
Dot pitch refers to the size of the color dots on the screen. The smaller the number, the sharper the display. Good quality monitors have a .28 to .25 dot pitch. Manufacturers may also refer to the maximum number of horizontal and vertical points (pixels) that can be displayed on screen. A 1024X768@75 Hz to a 1280X1024@75 Hz display is recommended for 17" monitors and 1280X1024@75 Hz is recommended for a 21" monitor. Note that some monitors and graphics cards will claim 1280X1024 resolution and 85 Hz refresh rate, but not at the same time. Make sure that you can get high definition and high refresh rates at the same time.
The picture should be crisp, with strait lines strait all the way to the edge. The screen should be flat or nearly so. Advanced monitors have all sorts of useful add ons such as "pin cushion" adjustments, adjustment memory and built in degaussing. These are niceties, especially if they are accessible from the front. The crucial element is picture quality.
Magnetic emissions are a possible health hazard. There are those who claim that magnetic emmisions can cause cancer or cause women to miscarry. If you want to be safe, get a monitor with low magnetic emissions. Sweden organizations have promoted a strict code for allowable magnetic emissions and low magnetic emission monitors will usually claim compliance to those codes (MPR-II and TCO-II). The other solution is to sit at least four feet from the screen. Magnetic emissions fall off sharply at a distance of four feet from the monitor.Getting four feet between you and the monitor while you're working will require a large monitor and a larger work space.
If your graphics card is designed to operate more than one monitor, a second monitor can display the command screen, word processors, spreadsheets or graphics programs. With the command lines moved to the other monitor, the drawing portion of the display screen is larger, while the command monitor displays back several commands and will display a list without the need to flip screens. A cheap monitor will often work.
Between the computor and the video display is a video processor, a graphics accelerator. It is usually a separate internal cirduit board plugged into the main system. You will need a good quality graphics card. Look for one with AutoCAD drivers. Often the time spent waiting on the computer is not time spent waiting for the central processor, but time spent waiting for the screen to redraw. This is entirely subject to the video processor. The rise of the PC gaming industry has radically lowered the cost of graphics cards. Be sure to get a graphics accelerator card designed for AutoCAD, (if that is your main graphics task).
Graphics cards in general and 3D graphics cards in particular are a complex subject. The card that gives an incredible speed boost to 'Doom' or 'Half-Life' may do very little for the next 3D modeling project in AutoCAD. Also the 3D modeling standards and drivers are changing rapidly. This is definately a good place to get dealer input.
The graphics card has its own video memory called Video RAM (VRAM) or Dynamic RAM (DRAM). Increasing the VRAM or DRAM from 2 megabytes to 8 megabytes will speed up video performance. It's a MegaByte thing, more is better.
Some graphics cards are designed specially for 3D models. AutoCAD2000 uses the proprietary Heidi 3D graphics system, and at present, has limited OpenGL support. OpenGL cards only work if they have full drivers for OpenGL 1.1 or above and have an OpenGL Installable Client Driver (ICD). The 'miniGL' driver provided with some cards will not work. Some 3D graphics cards are designed to work with 2D graphics cards, not by themselves.
If you have two monitors, get a graphics card that supports a second monitor or you may have to buy a second card. There are graphics cards available now that allow NTSC television input and output. Television output can be useful for creating flybys of CAD models on video tape. Television input can be used to capture background images. These are generally not the cards that will be the best CAD graphics cards. Your AutoCAD dealer can help select a good graphics card for your needs.
You will need a large hard drive. All your information is stored there. Get a good quality one, a fast one. CAD files are big, big, big. I filled a 100 megabyte hard drive in my first six months using AutoCAD Release 11, and that was before I started generating rendering files and three dimensional drawings. Complex drawings can have drawing files that are two megabytes or more in size. AutoCAD always makes a backup when you save a drawing, a 2 megabyte drawing actually takes 4 megabytes in memory. Exporting rendered images to raster files creates files that are 4 to 100 megabytes in size. I currently currently use an 8 megabyte disk, working from a fully loaded four gigabyte partition and keeping my files on a second 4 megabyte partition. To make more room, all old project files are stored on 100 MB zip disks.
One note about speed. Hard drive access speed is directly tied to the type of drive and the type of system bus. Using a slow hard drive is like tying a stone to your leg.
Removable hard drives are useful in several ways, they allow immediate expansion by changing hard disks, and they are an excellent way to transport very large files. More and more graphics houses and printing companies have removable hard drives available. Check with the local print shops to see if they have computor printing available and what sort of storage devices they have. Iomega's 'Zip' drive is popular and is therefore commonly used for sharing large files. There are other removable drives which offer greater capacity. I use a SCSI zip drive at the office and a parallel (printer port) zip drive at home. Transferring the same files from the same disk ten to twenty (not a scientific measure) times longer on the parallel drive. Enough said.
Read/write CD drives and floptical drives are other ways of getting large files in and out of the computer for storage or for transporting large files to be printed or plotted. The plot service would have to have a compatible drive to read files. Archival storage can be done on writable CD-R drives, which are inexpensive, use inexpensive media, and can be read by any standard CD drive. CD-R disks have an average 30 years life expectancy, which is higher than most other electronic media. Re-writable CD-RW disks cannot be read except on a compatable CD-RW player, and the disk media is more expensive making it less attractive for long term archival storage.
You must have a backup storage system. When someone reformats your hard drive, yes I have seen that happen, or the computer comes up with a virus and crashes, you had better have a backup. I have had two hard drives, both less than six monthes old, fail. A backup is a copy of all of your files. Make sure to keep current system boot disks. The Windows help file under 'Boot Disk, Creating' explains how to create boot disks which will help you recover from catastrophic failure. Virus checking software also has procedures for creating boot disks with virus checking built in. You must backup your files on a regular basis, preferably every day.
Murphy's Law applies to AutoCAD. BACKUP EVERYTHING!!!
Even if you have the original disks and can reload the programs, back them up regularly. Because all of your operating software has to be configured to your system and is customized to your tastes, the current load will no longer match the default settings of the freshly loaded software. AutoCAD and other programs allow for extensive customization of the look and feel of the program, as well as extensions or changes to menus, hatch files, line-types, etc. Backup everything once or twice a month. Backup all of your drawing files daily if possible. No one wants to backup several gigabytes or more of programs, drawing files and other files, but it is much easier to replace the hard drive than all of your drawings. There are easy solutions.
For very little money, a tape drive can make a backup of all of your files while you are at lunch or overnight. Be sure to get a tape drive capable of holding everything on one tape, (allow for expansion), since you may not be there to change tapes at 2 A.M. Many tape drives can backup the whole of a small networked system overnight.
Do not back up your files on the same hardware. If your files are stored on a removable hard drive, do not store the back up copies on another disk for the same drive. If the removable hard drive fails neither copy will be useful. Moreover the drive could fail in such a way as to make the disks unreadable to a replacement drive.
While writable CDW drives are a good way to archive drawings or to share drawings, they are not a good choice for daily backups. The cost of the CD's would not be cost effective. Re-Writable CDRW drives could be used as a program file system backup, but be aware that many CDRW disks are readable only by similar CDRW drivesand they can only be re-written a limited number of times. Tape drives are far more cost effective and effecient.
Most computors come with a mouse or similar pointing device. Not all come with a comfortable mouse or other pointer. Drafting requires a lot of manipulation of drawing elements on the screen. If your pointing device is not comfortable screen picks become awkward, your hand may cramp and soon suffer from carpal tunnel syndrome, shoulder strain or other repetative stress injuries.
A poor quality monitor causes eye fatigue, a poor chair causes backache and a poorly designed pointing device causes hand, wrist or shoulder strain.
I almost never use a digitizing tablet anymore. You may want a digitizing tablet. If you are working in DOS you will definitely need a digitizer. If you work in windows exclusively, and draw mostly from scratch, you will not need a digitizer. The digitizer is more than a mouse. A mouse allows you to move a screen pointer about the screen, and manipulate screen elements. The digitizer tablet contains an imbedded electronic array that allows a direct one-to-one position match between tablet and puck (mouse). Typical pointing devices transfer relative movements to the screen. The digitizer puck registers an exact location on the tablet, and the tablet transfers that data to the screen or anywhere else in the programmable computor world.
The digitizer allows you to set aside a screen interaction area on a portion of the tablet and to use the rest of the tablet area for other uses dictated by the AutoCAD or the tablet. The AutoCAD standard menu has a "tablet menu" built in that allows drafting commands to be invoked with a click on a cooresponding space on the tablet. This tablet menu is fully customizable and several alternative menus are available.
Alternately you can establish a scale match between the tablet and the CAD drawing. By picking points on a drawing taped to the tablet, the drafter traces ("digitizes") the drawing into AutoCAD. This is a quick way of getting simple blueprint data into an electronic CAD file without the need for a scanner.
If you often receive blueprints that need to be transferred into AutoCAD and wish to digitize them. It is worth the extra price to get a large digitizer. If your drawings are larger than the tablet pointing area (the space covered by the electronic array), you will have to move the drawing. This can be an annoying interruption and can introduce drawing errors. See: Appendix B.
You can usually use both the mouse and the digitizer on the same system. Many digitizers allow you to use the puck as a virtual mouse eliminating fumbling and desk clutter.
Test the feel of the cursor or puck. If you will be doing a lot of drafting the puck must be comfortable to grip. A poorly designed drafting puck will increase the risk of repetitive stress injuries. Many leading manufacturers have poorly designed pucks. The puck should be large enough to grasp comfortably and the heal of the puck should hold your wrist up off the tablet.
Most digitizers offer 4-button and 16-button pucks. I prefer the 16 button puck because it allows me to activate frequent commands (SNAP, COORDINATES, ORTHO...) from the puck, which greatly speeds the drafting process. Some tablets have pressure sensitive drawing pens available for rendering in compatible drawing packages. This allows for drawing with thick and thin lines, or heavy or light color washes that simulate drawing or painting by hand. While this is not useful in AutoCAD itself, those who wish to export CAD images to a drawing package for further embellishment should see if their tablet can be used with a pressure sensitive pen.
You will need some way to get the information out onto paper. You can send drawings out to an engineering copier service to be plotted. But sending plot files out to be plotted is time consuming and expensive. In the field of plotters there are lots of options. Pen plotters are very slow and difficult to maintain. Ink jet plotters are faster and more reliable and are the current best for low cost plotting. When idle for a long time, run a short plot now and again to keep the ink heads from drying out. Laser plotters are very expensive and very fast. Get a plotter that can handle your largest size drawing.
Cheaper is not necessarily better. Some plotters require frequent maintenance, which increases down time, usually at the worst possible time, and adds service costs. The consumables (ink cartridges, special papers, toners...) on some inexpensive plotters make them expensive to operate. Ask about a service contract. Even if you don't use one, the cost should give a hint as to the maintenance cost of the plotter.
You will need a printer for routine paperwork. Ideally, look for a printer that can print HPGL or HPGL/2 plot files on 11" x 17" paper. This is a great size for small shop drawings and check plots. There are several inkjet printers on the market that will print 11" x 17" plots and are reasonably priced. The price of 11" x 17" laser printers is dropping rapidly. Laser printers are much faster. Make sure the manufacturer has a driver for AutoCAD. Ask them to send you samples of AutoCAD drawings printed by the printer that you are interested in purchasing and ask how long it took to print.
Color is nice but not important to CAD drafting. But renderings of 3D models can produce startlingly photo-realistic color prints. With the cost of color inkjets, including 11"x17" printers, so low, it seems foolish to pass up the possibility. If you use the printer for seperate black and white output, make sure the black cartridge is seperate. Don't waste color ink, changing the black cartridge. There are several engineering inkjet plotters available in color, which produce incredible color design layouts at fairly low cost.
The modem is an essential part of the computer. A fast modem will allow you to download updated drivers and AutoCAD patches, (code repairs), off of Bulletin Board Services or the Internet. There are several AutoCAD services on the Internet, including AutoCAD courses, news services, project hosting, download sites, and construction materials information or drawings. It is easy send drawing files across the world through E-mail or post them on web sites.
Get an Uninterrupted Power Supply (UPS), a battery backup power supply with surge protection. I have experienced countless power outages while working at the computer, but never lost any data because of battery backup systems. Speakers are fun but only useful for demos and training CD's, (and, of course, games).
There are two ways to get hard copy blueprints into electronic files. Scan the drawings with a flatbed scanner., and digitize them. A scanner scans the drawing and turns what it sees into and electronic picture file. As explained above, the digitizer allows you to trace a drawing directly into an AutoCAD file.
A page scanner can be very useful for scanning small drawings into AutoCAD. You may also need Raster-to-Vector conversion software. Generally anything you scan requires a great deal of clean-up. Once scanned, the drawing is turned in to a raster file. A raster file records the drawing as a series of dots. An engineering size scanner is roughly the cost of a plotter. If you need to pull in large paper drawings, I get fewer and fewer, concider buying a larger digitizer and tracing directly into AutoCAD.
The raster file from the scan can be imported into AutoCAD and traced on the screen. The process is easier than digitizing, since digitizing divorces the tracing (on screen) from the item being traced (on the digitizer). When tracing on screen, both images are superimposed.
Another approuch is to convert the raster file to a vector file using separate translation software. The vector file is a file consisting of lines, arcs and circles (like an AutoCAD file). The vector file is then imported into AutoCAD. Only then is the file a genuine AutoCAD drawing file. At this point, you will have to clean up the drawing since the converted image is gernerally very ragged.
Commercial companies will scan your old drawings for you. If you want them to clean the scan up and create a proper AutoCAD file, it will cost money and you will have to wait. Unless you have a need for your older drawings to be translated into AutoCAD files, let them be. If you are thinking of scanning it all yourself, do not forget that the price of an engineering size scanner is only the beginning of the process. Many companies will tell you that their software is great at recognition and will produce faithful representations. Do not believe them. Expect to have to spend a large amount of time making wiggly lines into clean lines and arcs. As for character recognition, for those that attempt character recognition for AutoCAD, you will spend more time fixing the text than you would typing the text in the first place.
Add to the full computer setup disks, tapes, a tall desk, additional software, security devices, etc. AutoCAD itself is very expensive. AutoCAD will cost the price of a computer. When the grocery list is tallied up, you will be looking at a system that costs from around $7,000 to over $40,000. For most theaters this is a sizable investment. For many it will already be prohibitive. Let me re-emphasize, before investing any money, talk to your dealer. Hardware is rapidly changing and being improved. Some devices do not work well with AutoCAD.
It is important that you find a knowledgeable and helpful dealer. Your dealer should be staying abreast of market changes and can advise you on the compatibility and reliability of hardware. Take your time selecting a dealer. Dealers also sell hardware, so their advice may be designed to promote their hardware sales. Make sure to ask hard questions and expect good answers. A dealer that is little more than a sales clerk is likely to be a poor source of advice and will not be helpful when you struggle with compatibility problems. AutoDesk, AutoCAD's mother company, does not directly support the end user, the dealer does, so choose wisely.
Setting up for an AutoCAD drafting station is not greatly different from setting up for hand drafting, except that the tools are radically different. You will need a clean, quiet space that is secure at night. There has to be a lot of room for laying out drawings and places to store them all when you finish. Do not get in a hurry to throw away all the old hand drafting equipment.
As for the station itself, you will want the keyboard and monitor(s) directly in front of you, and the digitizer or mouse directly to the right of the keyboard (assuming that you are right-handed). The monitor should be at eye level, so you are not looking up or down constantly. The affects of magnetic emissions from the monitor are very slight if you are at least four feet away, so don't arrange yourself too close the screen.
Try to arrange things so that you have light on your drawings, but not on the monitor. Too much light on the keyboard, yourself or the wall behind you will cause an annoying reflection in the monitor. The glare from light sources reflected in the monitor, like a door or window behind you, will give you a headache. Glare screens are a poor substitute for well designed lighting. Peering through a glare filter is similar to staring out a dirty window.
Get a desk or table that is drafting height, and drafting stool to match. The opera's carpentry crew made me a set of decorative blocks to raise my office desk. Although, the drawing you do will not require as much reaching as hand drafting, you will still be referring to large blueprints. Sitting in a drafting chair allows more movement and makes reaching easier.
Typically a CAD workstation is an high L-shaped desk. The monitor is in the corner. CAD monitors are larger 19" or 21" monitors which are deeper than the average desk allows. By placing the monitor in the corner, it is easier to get the proper distance between you and the monitor. Placing the keyboard to the side is not recommended as you would have to twist your neck continually.
The computer, if it is not directly under the monitor, must be close. Manuals, reference books, disk storage and the telephone should be in easy reach. You will need at least one drafting table or large desk next to you for laying out large drawings while you work. Don't force yourself to do gymnastics every time you turn to look at your stack of drawings. Printers, scanners and plotters should be close by, but they can be on the other side of the room, or even out in the hall, if necessary.
You will need a lot of room. If you also have map drawers, an engineering copier, and typical stage paraphernalia, your office might need to be bigger than the boss's office.
CAD drafting narrows the range of physical activity of the drafter considerably. In traditional hand drafting, the drafter is moving about the drawing, manipulating a parallel rule or drafting machine, and fishing in the drawer for pencils, pens, templates and erasers. In CAD drafting, all motions tend to be confined to a very small space. As a result the same muscles and tendons are being constantly worked in the same way, which can inflame tendons or nerves causing various Repetitive Stress Disorders, the most well known of which are "Tennis Elbow" and Carpale Tunnel Syndrome.
Part of setting of the workstation is adjusting the chair, keyboard, mouse, etc. so that you prevent unnecessary stress to your body:
Fight the narrowing affect of input to the computer by frequently changing where the mouse is placed, (or the digitizer menu), getting up and stretching, and frequently pulling your eyes off of the screen and focusing on some distant spot. This is particularly important for full time drafters whose health can be permanently damaged by endless repetition in hand movement, posture, visual focus.
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