topic Re: Arc Lines not Plotting as Drawn in AutoCAD LT Forum

Arc Lines not Plotting as Drawn

Anonymous — Mon, 19 Mar 2018 17:51:51 GMT

Hey there, it's my first time posting here so I hope it posts properly 😉

I'm having some issues plotting with my newest version of AutoCAD. I’m using AutoCAD LT 2017. I frequently plot single line full scale paper templates. I plot them on an HP Designjet 500. I’ve used the same process for over 10 years without an issue…until now. What I’m running into is that the arc line drawn in the model space isn’t previewing the exact same, and what’s previewed is actually what’s plotting.

Here are some images to show what’s going on.

This is the original I’m trying to plot, as drawn in the model space. I print with a window around the rectangle, which matches my paper size, and print as 1:1

Here’s a plot preview of the arc shape, zoomed in on the overall shape. If you notice both ends of the arc are now closer towards the center then they were (narrower then the dimension line), and the center of the arc is now higher then it was (above the dimension line):

Here’s zoomed in on the lower left corner:

And zoomed in on the center of the arc, at the top:

The actual plotted arc measures how the preview looks, measuring roughly 3/16” narrower and 1/8” taller than drawn. The plotted dimensions measure correctly. This doesn’t happen all the time, it seems to be somewhat random, and I’ve never had this issue before I started using AutoCAD LT 2017. I can sometimes fix the issue by redrawing the arc as a circle trimmed, or as different types of arcs. As long as the plot preview looks right, it'll print correctly. The one in the above pictures didn’t seem to want to work at all, no matter how I drew the arc.

I ended up trying it as a circle with the lower portion outside the plot window, which looked like this:

The plot preview drew the arc correctly this time, although it now has the arc extended on the bottom:

Any ideas on how to correct this?

Thanks

John

Re: Arc Lines not Plotting as Drawn

rkmcswain — Mon, 19 Mar 2018 18:13:29 GMT

Never trust the display on your monitor. Use the measuring commands to test if something is drawn correctly.

As far as the plot itself, are you saying that this discrepancy is large enough to be noticeable/scale-able on paper?

Re: Arc Lines not Plotting as Drawn

Anonymous — Mon, 19 Mar 2018 18:49:04 GMT

The actual arc line that's plotted is measuring roughly 3/16" narrower and 1/8" taller then what was actually drawn in the model space, so yes quite noticeable. The dimension lines on the plotted paper are measuring correctly though. The arc line is changing size from how it's drawn to when it's plotted. It's showing the wrong size when doing the plot preview as well, see pics above for reference. This makes me think it's an issue with AutoCAD, not the plotter, since the print preview is wrong as well. What's shown on the print preview is what gets plotted, but it doesn't match the model space. Has anyone even ran into this?

Re: Arc Lines not Plotting as Drawn

pendean — Mon, 19 Mar 2018 20:34:50 GMT

Post your DWG file, point to a few dimensions that are off, ensure your DWG file is ready to plot based on the settings you last used that resulted in the error.

Re: Arc Lines not Plotting as Drawn

john.vellek — Fri, 23 Mar 2018 19:12:59 GMT

Hi @Anonymous,

Is it possible to attach your file so I can examine this behavior? I am happy to see if I can help get this working properly for you. Please make sure that you have applied a Page setup and include any plot styles you use when plotting.

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: Arc Lines not Plotting as Drawn

Anonymous — Mon, 26 Mar 2018 12:53:52 GMT

Here's a copy of the dwg. The page setup is named Plot Issue, and the plotter setup is named Main Plotter. Thanks

Re: Arc Lines not Plotting as Drawn

Anonymous — Mon, 26 Mar 2018 19:16:51 GMT

So I did some trial and error testing to try to determine if there was any type of consistency to this issue, and it turns out there is. It seems to depend on the width/height ratio of the curved segment. The closer to a half round the worse it is.

I tried a variety of heights and modified the widths until this print preview issue was shown. So at a height of 30”, the min width I could use without causing the issue was 62-1/2”. Anything above 62-1/2” was fine. 62-7/16” and below would cause the issue.

Here’s some other heights and the min width without causing the issue:

30” high – min width 62-1/2”

28” high – min width 58-9/16”

25” high – min width 52-9/16”

22” high – min width 46-9/16”

16” high – min width 34-7/8”

10” high – min width 22-13/16”

I’m still not sure why this is happening though…

Re: Arc Lines not Plotting as Drawn

john.vellek — Mon, 26 Mar 2018 20:23:09 GMT

Hi @Anonymous,

I increased the unit precision in your drawing and found that the arc was not drawn "perfectly".

I tossed in a circle with a 11" radius and then plotted to PDF. When I measure in the PDF, I find that the distance measures correctly. I have re-attached your file with my changes. Can you try it again?

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: Arc Lines not Plotting as Drawn

Anonymous — Tue, 27 Mar 2018 11:32:28 GMT

Thanks for looking into this for me. Unfortunately that didn’t fix the issue. You’re new file still has the same issue when I print preview with my HP Designjet 500 plotter. It’s only happening with that device. I can take the original file, or the test ones I did that had the same issue, and preview them with other printing devices (including a PDF writer) and they all look fine. I think it has something to do with AutoCAD misreading to my plotter. It’s a very old plotter and maybe the newer version of AutoCAD can’t communicate properly.

Re: Arc Lines not Plotting as Drawn

Anonymous — Tue, 27 Mar 2018 12:36:22 GMT

I just tested this on an older version of AutoCAD 2011 that’s on another computer and it previewed fine. I tested it using both the “HP Designjet 500” in the plotter devises and the “Main Plotter” plot setup (which was setup the same as on my computer).

Then I tested it on my computer again using the “HP Designjet 500” instead of the “Main Plotter” and it previewed fine. I switched it back to “Main Plotter” and the issue’s back. So now I’ve pinpointed to my “Main Plotter” plot setup. The “Main Plotter” is a direct copy of “HP Designjet 500”. The only difference is that it was calibrated with AutoCAD.

So why would it only do it when the plotter’s calibrated with AutoCAD (not the un-calibrated version), only with AutoCAD 2017 (not with 2011), and only for certain sizes (as I showed above)?

Re: Arc Lines not Plotting as Drawn

john.vellek — Tue, 27 Mar 2018 13:47:20 GMT

HI @Anonymous,

I am glad that you have narrowed it down to the one driver. IF it is not happening with the uncalibrated setup then go with that configuration. That plotter was certified for Windows Vista and was actually designed during the Windows 2000/XP era. There are some universal print drivers that might be worth trying too. Unfortunately, the hardware is great and will last a long time but the obsolescence of the drivers makes this tough to remedy.

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: Arc Lines not Plotting as Drawn

Anonymous — Tue, 27 Mar 2018 14:01:43 GMT

Unfortunately I can’t use the un-calibrated version because it doesn’t print to the proper scale. The templates I’m printing have to be exactly 1:1 scale with the dwg. Without being calibrated the print can be up to 3/8” in the difference which won’t work.

I did discuss this with our tech and figured it might be a driver issue but we have all we could find. Where would I find the universal drivers?

Thanks

Re: Arc Lines not Plotting as Drawn

john.vellek — Tue, 27 Mar 2018 14:31:14 GMT

HI @Anonymous,

Here is a link to the driver I found on HP's site. I hope this is a viable option to resolve the issue.

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: Arc Lines not Plotting as Drawn

john.vellek — Thu, 29 Mar 2018 21:44:10 GMT

HI @Anonymous,

Did the Universal Driver correct this behavior for you?