topic Re: Plotting not precise when using very small Plot Scale in the Plot dialog in AutoCAD Forum

Plotting not precise when using very small Plot Scale in the Plot dialog

Anonymous — Wed, 29 Nov 2017 11:03:03 GMT

We have a problem with a specific file that is set with a very small plot scale factor in the plot dialog window.

Since we usually work in meters, and the layouts are set in mm we find it easy to set tis scale to 1000mm = 1 unit. However for this specific file it was set to 1mm = 0.001 unit Witch I thought would be same…

Now Autocad always automatically changes the 0.001 into 0.001012 units, no matter how much I change this setting in the page setup manager. It seems he loses precision with this very small numbers. When we print the file like this, the scale is of, really off, even more than the 1% you might expect (2-3% I would estimate)

This bug disappears when I set the scale to 1000mm = 1 unit and then save the file. I can even return to the 1mm = 0.001 units setting with no problem!!

Another weird detail about this, when I switch between inch and mm (still at the plot scale in the plot dialog) Autocad automatically puts 0.0257 for the units, and not 0.0254 as you might expect.

I don’t really have further issues with this file, I solved my problem (just putting 1000mm=1unit and then save). I just want to know if this is a known bug, or something I might do wrong?

I just want to prevent printing imprecisions in the future.

Thanks a lot for any help!

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

pendean — Wed, 29 Nov 2017 13:36:29 GMT

>>>...we usually work in meters...<<<
In your screenshot, that scale is based on 1mm, not the same thing as meters.

Are you plotting from modelspace? Why not use paperspace?
Why not use the pulldown next to the word SCALE to select a scale you want or need? If it's only because you cannot find the one you need then explore using SCALELISTEDIT command to create the one you need.

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

Anonymous — Wed, 06 Dec 2017 11:20:24 GMT

Yes, we are always plotting from paperspace. And what I meant was that we draw in meters in model space and we use paper space in mm. So to be able to print nicely with the predefined scales we scale 1 to 1000 just before printing in the printing dialog window.

But you are right, SCALELISTEDIT is an interesting solution. Although i prefer not to change autocad too much from the “standard install". We are a small office, we don’t really have an IT department that can keep track of this throughout the office and with changes of computers etc...

But my concern remains. Does Autocad lose precision when printing from paperspace at scales around 1 to 1000 (or .001 to 1) in the printing dialog window? Are these kinds of settings to be avoided? Or am I missing something else?

Big thanks,

Pieter

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

pendean — Wed, 06 Dec 2017 15:49:38 GMT

There is no such thing as "standard install" when it comes to AutoCAD: AutoCAD is a fully customizable CAD program designed deliberately for you to take control and set it up to do what you want as much as you can to get the result you want.

So do so, we all do it, we tell AutoCAD what scales to show us using SCALELISTEDIT, we tell AutoCAD which printers to use, we tell AutoCAD what plot style settings we want to see, we tall AutoCAD what layers we want/what to call them/what colors they are/what linetypes they are.

If you want a closed up CAD program, save a ton of money and switch to something like Microsoft Visio.

Try it now: own it. Don't fear it. Your company paid a ton of money for this program, use it fully. This is not a software to use Out-Of-the-box as is, that is a complete waste of your billable time at the office. Trust me.

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

Anonymous — Thu, 07 Dec 2017 12:12:47 GMT

Ok, I was not really searching for an assessment of my efficiency in AutoCAD. (I don’t think Visio will do the trick, but thanks for the insight)

So somebody else has a thought on this?

Can I use the plot scale setting in plot dialog window with scales that are a little more extreme like 1mm = 0.001 unit? Or is this not recommended? Nobody uses tis scale setting?

Greetings

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

pendean — Thu, 07 Dec 2017 12:28:52 GMT

May I ask why you wish to fight/ignore the tools already in place and provided to you in AutoCAD?

Your desired method is not the correct method: the tools I outlined exist to do what you want.

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

rkmcswain — Thu, 07 Dec 2017 12:48:23 GMT

pieterdgrv wrote:

....SCALELISTEDIT is an interesting solution. Although i prefer not to change autocad too much from the “standard install". We are a small office, we don’t really have an IT department that can keep track of this throughout the office and with changes of computers etc...

Creating a scale factor and naming it is not changing AutoCAD, any more than adding a new layer would be. If you always needed a layer named "LIGHTS", you'd add it to your template drawing once so you don't have to do it every time, right? Same goes for a scale list entry

This has nothing to do with an IT department and changing computers, etc.

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

StephenThomasGrace — Thu, 07 Dec 2017 13:23:38 GMT

This may be of help.

Like you, I always use meters for my model space drawing units.

In paper space my Title Blocks, which are defined in millimetres, are inserted with a scale factor of 1000.

This is because the titleblock UNIT is mm and the drawing UNIT is m... anyway after insertion the ISO B1 sheet is 1000 units long and is always plotted at 1:1. (automatic block scaling at work when dissimilar units used)

For my viewports I always use custom viewport scales and always append (m) to the name to differentiate.

AutoCAD does not come with any preset drawing scales to handle m to mm like Civil 3D does.

so the plain AutoCAD 1:50 scale is 1 paper unit = 50 drawing units.

My custom 1:50 (m) is 1000 paper units = 50 drawing units. ( like doing a Zoom 1000/50XP)

This also works perfectly for annotative objects. (So I would suggest using a method similar to this)

Save all your custom scales in your template (and get rid of ones you do not use)

Since Plotters are generally expecting mm or inches, I think it is best to have your paperspace use one of those units.

Setting up your paper space in metres and plotting to a reduced scale as you appear to be doing should work.

I've just plotted using your 1 to 0.001 and got an acceptable result. I was only out ~1mm over 1000mm.

I cannot get it to reproduce your wayward scale precision.

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

AllenJessup — Thu, 07 Dec 2017 13:25:36 GMT

I think the change in value is somehow linked to the fact you're plotting by Window with offsets. If you create a layout that is at a size you want and a size your plotter is able to print. Then you can plot by layout. This will allow better control over the results and you will only need to change the scale of your viewport to plot at different scales. This method eliminates the the need to specify a Window or an offset or center the plot.

Borders and Titleblocks in Paperspace should be created at a 1 to 1 scale. I don't know what border size you're aiming for but it should fit within your 919.90 X 1599.90MM paper size (or whatever your printer/plotter will handle). Then you can plot at 1mm = 1 unit. Scaling of modelspace objects in the viewport is controlled by the viewport scale.

It's likely that you can scale your current border to fit the new layout. So it shouldn't be a time consuming process. You'll gain time in the future not having to fight the program.

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

AllenJessup — Thu, 07 Dec 2017 13:36:52 GMT

@StephenThomasGrace wrote:

AutoCAD does not come with any preset drawing scales to handle m to mm like Civil 3D does.

Thank you. I didn't know that. This is how I have our metric Template set up:

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

JDMather — Thu, 07 Dec 2017 21:40:34 GMT

I have always plotted Layout.

I have always plotted 1:1.

Scale is set in layout viewports, not in plotting.

Set it in templates and forget it.

Every print comes out correct without issues.

Maybe I have been doing it wrong for years?

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

rkmcswain — Thu, 07 Dec 2017 22:45:58 GMT

@JDMather - I remember the uproar when R2000 came out with MDI and they changed plotting all up... but in hindsight, that was one of the best changes they ever made to AutoCAD.

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

AllenJessup — Fri, 08 Dec 2017 12:52:31 GMT

@rkmcswain Or the introduction of Paperspace (Tilemode 0) in R11. That also changed plotting in a big way.

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

JDMather — Fri, 08 Dec 2017 17:21:46 GMT

@Anonymous

Are you still there?

Would you like to solve this problem for all time?

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

steven-g — Fri, 08 Dec 2017 20:15:58 GMT

I'm not sure what I'm missing here, but what are your drawing units, and what paper sizes are your layouts, I always use millimetres but often come across drawings from architects who use meters and quite often centimetres is the unit of choice. But whatever is used if your layouts use metric paper sizes A0, A1, A2, A3, A4 and you run the -dwgunits command pick meters from the first list, at the next prompt choose display format as required and precision as you want, then answer yes to all the following prompts, Autocad automatically adjusts all the scales for you so 1:1 is converted to 1mm = 0.001 units and all other scales are adjusted to suit, the only time it gets weird is if you have imperial paper sizes.

Re: Plotting not precise when using very small Plot Scale in the Plot dialog

Anonymous — Wed, 10 Jan 2018 16:21:11 GMT

Thanks a lot for all the helpfull insights.

Nobody seems to use the scale setting in the print dialog box. So maybe i shouldn't either 🙂

Is true that i only had the scale problem with this particular setting.

from now on i ll go for the scalelistedit!

Thanks,