17. Plotting a drawing on a plotter

AlfaCAD can work with a vector pen or cutting plotter equipped with an interpreter of practically any command language, like HP-GL (Hewlett Packard Graphic Language). Most of the produced plotters are equipped with this interpreter, including plotters by Hewlett Packard, Huston Instruments, OCE Graphics, Muttoh, Versatec, Roland, Graphtec and many others. The procedures with which AlfaCAD is equipped allow you to define all the necessary instructions to control the plotter's head, thus enabling plotting of a drawings using devices of any type and format.

Nowadays, the role of vector plotters has been taken over by large format printers (or raster plotters) that print in the same way as graphic or photo printers. AlfaCAD, however, does not forget about those who still use such plotters, or who use, for example, cutting plotters, to cut shapes on self-adhesive foils.

The program allows plotting different types and colors of lines (and other objects) with pens of different thickness or color of ink. It also allows plotting in any scale, with the possible rotation of the sheet, shifting the drawing format in relation to the base point of the plotter's working area, which allows plotting of several small drawings on one large sheet of paper or tracing paper.

The function of plotting a drawing is initiated from the menu / File / in the option / Legacy plotting / .

The plotting dialog box includes the following parameters:

Pen speed / Thickness

Pen speed is a feature of vector (pen) plotters. This parameter is ignored in the case of inkjet plotters (raster plotters equipped with an HP-GL command interpreter, printing in the same way as graphic printers, where the concept of a pen has only a logical meaning, allowing the virtual pen to be assigned its color and thickness, and the speed parameter is omitted ). The speed setting may be replaced with the default setting by typing "X" in place of the numerical speed value.

Pen plotters are usually equipped with a maximum of 8 pens, therefore the dialog box contains 8 edit fields for editing the speed of pens with numbers from 1 to 8, expressed in [cm / s].

In addition to the pen speed parameter, the program allows you to declare the thickness of each of the 5 line thicknesses, from the thinnest to the extra thick. Thickness declaration is only applicable for inkjet or laster raster plotters. The condition for configuring the pen thickness by the program is to enable the " ink plotter " option in the " Rotation, window, color" parameter group.

An additional parameter in this group is the "filling" parameter. It allows you to define the approximate thickness of a pen for filling such objects like solids, traces and disks. Taking a lower value gives a higher guarantee of accurate filling of areas, with a simultaneous extension of the plotting time and the number of vectors plotted. The number of plotted vectors may be important in the case of roller plotters, where the number of sheet roll movements should be minimized, due to the possibility of plotting inaccuracies as a result of the unavoidable deformation of the paper sheet edge, subject to constant pressure by the plotter's rollers. This causes a certain elongation of the edge of the paper or tracing paper, and thus its deformation, hence possibly a slight but albeit increasing shift of the print coordinates relative to the initial coordinates.

In the case of drawing texts, for raster inkjet plotters, the line thickness is adjusted proportionally to the text height.

Pen numbers

The pen number for each of the basic (16) colors is declared for each of the 5 line thicknesses.
The buttons below the number column are used to copy to the pen number column in the first row.
The buttons to the right of the row are used to copy the pen number in the first column in the row.
The button in the lower right corner of the rows and columns field is used to copy to all pen number fields in the first column of the first row.
The button in the upper left corner of the rows and columns field is used to return to the previous state of the fields, in case of pressing one of the other buttons by mistake.
These buttons allow to edit all fields faster if the pen numbers for colors or thickness are unified.

The program plots with sorting of pens (first all objects with lines assigned to the pen with the lowest number are plotted).

Rotation, window, sheet, color

The drawing can be plotted rotated by 90ยบ.

Selecting the "Window" option allows you to select a drawing fragment to be drawn.

Selecting the "Sheet" option allows you to select the so-called a printout sheet described in chapter " 16. Printing a drawing on a printer".

Objects are cut to the edge of the drawing format or to the edge of the selected window (" window " drawing option ), or block frame @SHEET ("sheet" drawing option). In the case of plotting on a table plotter, objects are additionally clipped to the size defined in the ALFACAD.INI set for a given plotter type - the format of the plotter's working area.

The options "Color", "Ink plotter" and "255 colors" apply to plotting on inkjet (or laser) raster plotters.

If the "Ink plotter" option is selected, the program controls the settings of the virtual pens in terms of thickness and color.

If the "Color" option is selected, the color of the virtual pens is matched to match the color assigned to each object. This color is defined as the color saturation (C, M, Y) ("Cyan, Magenta, Yellow"). For non-color printing, the color of the virtual pens takes the values (0,0,0).

When "255 Colors" is selected, a palette of 255 colors is used to define the pen colors by converting the RGB (Red, Green, Blue) colors of the color components assigned to each drawing object to the plotter's CMY color.

Set page dimensions (HP plotters)

This parameter is used when the plotting is made "from a roll" and the drawing sheet is not "proportional", ie eg narrow and long, or when the drawing simply exceeds the length of the A0 format. Select this option when plotting on a Hewlett Packard inkjet plotter.

Scale, shift

The program allows plotting in any scale. Scale refers to the drawing format, not the units and scale used for the coordinates of objects. If the drawing format has X; Y dimensions, these dimensions are kept to the 1.0 scale and reduced twice to the 0.5 scale.

The shift dx, dy expressed in [mm] allows you to print several small drawings on one large sheet, which turns out to be very convenient when using a large format (A0, A1) roller plotter.

In the ALFACAD.INI configuration file, in the [Plotter] group, a variable is defined that determines the way of centering the drawing:

Centering = 0; for an flatbed plotter with point <0,0> in the lower left corner
Centering = 1; for a drum plotter with a point <0.0> in the center of the sheet

Printing to the file / port

The default plotting target is the output file with the same name as the drawing name but with the .PLT extension . If the "constant name" option is selected, the once-declared file name is remembered and is the default name for plotting subsequent drawings.

If, when plotting directly on the plotter, the name (port) of the shared printer, local or network should be set instead of the file name, the printout will be sent directly to the plotter, without creating the result file, e.g. \\ TP123 \ HP_plotter

Saving and restoring plotting parameters

When plotting drawings of different sizes and using different plotters, it may be useful to save a specific configuration, and restore it when needed again. Saving the configuration in files with the .kpl extension does not impose any limitations on their number, which allows for convenient use of many configurations depending on the size of the drawing format and the currently used plotter.