Fine-Tuning PostScript File Export

AutoCAD provides the PostScript user with a great deal of control over the formatting of the Post- Script file that is output with the File Export and Psout commands. The options range from font- substitution mapping to custom PostScript prologue data.

However, you need to master the PostScript programming language to take full advantage of AutoCAD PostScript output. Most of this control is offered through a file named Acad.psf . This is the master support file for the Psout command. You can customize the PostScript file created by Psout by making changes in the Acad.psf file. Acad.psf is divided into sections that affect various parts of the PostScript output. Each section begins with a title preceded by an asterisk: the *fonts section lets you control font substitution, for example.

You will also want to know about the Psprolog system variable, which instructs Psout to include your custom prologue statement in its PostScript output. You add your custom prologue to the Acad.psf file by using a text editor. The prologue should begin with a section heading that you devise . The heading can say anything, but it must begin with an asterisk like all the other section headings. Everything following the heading, up to the next heading or the end of the file, and excluding comments, will be included in the Psout output file.

Tip	A complete discussion of Psout PostScript support is beyond the scope of this book. If you are interested in learning more, consult the PostScript section of the AutoCAD Customization manual.

You can also add a PostScript plotter to the plotter configuration. When you do this, AutoCAD plots the drawing as a series of vectors, just like any other plotter. If you have any filled areas in your drawing and you are plotting to a PostScript file, the vectors that are used to plot those filled areas can greatly increase plot-file size and the time it takes to plot your PostScript file.

Memory and AutoCAD Performance

Next to your computer's CPU, memory has the greatest impact on AutoCAD's speed. How much you have, and how you use it, can make a big difference in whether you finish that rush job on schedule or work late nights trying. This section will clarify some basic points about memory and how AutoCAD uses it.

AutoCAD is a virtual memory system. This means that when your RAM memory resources reach their limit, part of the data stored in RAM is temporarily moved to your hard disk to make more room in RAM. This temporary storage of RAM to your hard disk is called virtual memory paging. Through memory paging, AutoCAD will continue to run, even though your work might exceed the capacity of your RAMThe Windows operating system manages this virtual memory paging. If you have several programs open at once, Windows will determine how much memory to allocate to each program. AutoCAD always attempts to store as much of your drawing in RAM as possible. When the amount of RAM required for a drawing exceeds the amount of physical RAM in your system, Windows will page parts of the data stored in RAM to the hard disk. Your drawing size , the number of files you have open in AutoCAD, and the number of programs you have open under Windows will affect how much RAM you have available. For this reason, if your AutoCAD editing session is slowing down, try closing other applications you might have open or closing files that you are no longer using. This will free up more memory for AutoCAD and the drawing file.

AutoCAD and Your Hard Disk

You will notice that AutoCAD slows down when paging occurs. If this happens frequently, the best thing you can do is add more RAM. But you can also improve the performance of AutoCAD under these conditions by ensuring that you have adequate hard-disk space and that free hard-disk space has been defragmented or optimized. A defragmented disk will offer faster access, thereby improving paging speed.

Windows dynamically allocates swap-file space. However, you should make sure that there is enough free space on your hard disk to allow Windows to set up the space. A good guideline is to allow enough space for a swap file that is twice the size of your RAM capacity. If you have 256MB of RAM, you need to allow space for a 512MB swap file (at a minimum). This will give your system 512MB of virtual memory. Fast, high-capacity, multi-gigabyte hard disks are fairly inexpensive, so if you are running out of space, you might want to consider adding another hard disk.

Keep Your Hard Disk Clean

If you are not in the habit of emptying your Recycle Bin, you want to get into the habit of doing so. Every file that you "delete" using Windows Explorer is actually passed to the Recycle Bin. You need to clear this out regularly. If you are a regular Internet user , check your Internet cache folder for unnecessary files. You can employ one of the many hard-disk cleaning utilities to do this. Finally, it is a good idea to perform regular maintenance on your hard disk to keep it clear of fragmentation and unused files. The Tools tab of the Properties palette for your hard disk offers error-checking and defragmenting options.

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