CompuServe Thread

#Plot File Plotting Help

4 messages in this thread
#21995From: TIM MIREURNov 25, 1991 10:46 PM
We plot our plot files to a HP Draftpro and we couldn't get around the inherent shift problem except by using a plot origin of 0.18, 0.78 in stead of the normal 0,0. We got that simply by plotting one of our borders and measured the shift. Hope this helps and good luck. Tim
#22097From: David GariNov 26, 1991 3:26 PM
There are two "problems" really. I prefer to call them "misunderstandings". When AutoCAD plots directly to the serial port it interrogates the plotter for its "Hard Clip Limits". This is the physical size of the sheet MINUS the border. The plotter measures each sheet that you load and returns the maximum x and y motion of the pen. AutoCAD automatically locates the origin for the plot in the lower left corner of these limits. Misunderstanding #1: When you plot to a file, AutoCAD can not interrogate the plotter and so cannot determine the origin. The default origin for most HP plotters is in the very middle of the sheet. AutoCAD offsets the origin based on the plot size; it takes it on faith that you have told it the correct plot size. AutoCAD has pre-programmed plot sizes with an ARBITRARY 1/2" border all around. For example, a D-size sheet is physically 34" x 22" and when you pick "D" at the AutoCAD plot size prompt, it enters 33" x 21" for you. Misunderstanding #2: The plotter can't do that. It can't reach to within a 1/2" of the edge all around the paper. Check the plotter manual and you will find that in some cases, over an inch is required for the border. At the AutoCAD plot size prompt type in the width and height of the plot size based on the capabilities of the plotter. Here is a way to visualize the HP plot-to-file shift problem. Let's pretend that you have a big fat E-size sheet in the plotter. You send a small A-size plot. When AutoCAD is driving the serial port directly, it places the plot in the lower left corner of the paper. When you send the same plot to a FILE and then to the plotter, it lands right in the middle of the sheet (see #1 above). Suppose you told AutoCAD that the plot was C-size. A C-size plot would land right in the middle as well. [More]
#22140From: Craig Sharp [Mem TM]Nov 26, 1991 7:27 PM
David: Here's a simple way to handle what you're talking about… Create a block with ticks at the corners of a full size sheet (say, 30×42). Set the limits from 0,0 to the plotter's available plot area. If you're using a drawing border, insert the border so that it will plot correctly when plotting limits directly to the plotter, with all of the appropriate space around the border (this takes some experimentation…). Insert the block with ticks so that the sheet edges are the required distance from the drawing border. Use all of this as a standard, redefining the insertion points for the drawing border and the ticks block with 0,0 as the insertion point (without moving them…). Plot Extents to a file or to an electrostatic/laser plotter. Plot Limits directly to the plotter. Set up limits and insert both the block with ticks and the drawing border using the appropriate scale factor for each drawing. C#
#22098From: David GariNov 26, 1991 3:27 PM
[Continued] So you see that if you told AutoCAD the correct hard clip limits for an E-size plot, it would fill the sheet and the origin would land at the lower-leftmost corner (see #2 above). If you plot to a file with most HP plotters, the bottom line to remember is: tell AutoCAD the correct plot size (hard clip limits) for the piece of paper in the plotter, and leave the origin at 0,0.