topic Re: autocad precision in AutoCAD Forum

autocad precision

zanetto — Fri, 25 Mar 2022 13:17:04 GMT

i use units command and set precision=0

I draw a line of 20

I measure it and i obtain 20,03

I draw again the line

I measure it and i obtain 20,08

I need to obtain 20

Hoa can I do?

Re: autocad precision

pendean — Fri, 25 Mar 2022 13:21:19 GMT

Share with us your DWG file with a line of 20 that "measures" 20,03 20,08 please, lets see your work for ourselves.

Betreff: autocad precision

cadffm — Fri, 25 Mar 2022 13:21:34 GMT

Hi,

Share your dwg and mark the line,

this way we can see your issue without asking 20 questions.

Re: autocad precision

ChicagoLooper — Fri, 25 Mar 2022 13:45:04 GMT

@zanetto wrote

<<...I measure it and i obtain 20,03...>>

Please explain what you mean by 'measure it?' If you select it, does the properties palette display the precision correctly? If you measure it using a dimension line then you'll need to change the precision in the Dimension Style.

Re: autocad precision

Kent1Cooper — Fri, 25 Mar 2022 14:36:00 GMT

And I would add: Describe exactly how you "draw a Line of 20." Do you float the cursor along, without Snap turned on, until the display says you're 20 units away, and then pick? Then it will be subject to the rounding in your units settings, so what you see will be rounded in display, and what you see may not be what you get. If you aim the cursor in the direction you want to go, and type in 20, or you type in a relative displacement for the second point, such as [if to the right] @Anonymous<0, he resulting Line should be exactly 20 units long.

Re: autocad precision

zanetto — Fri, 25 Mar 2022 14:44:53 GMT

I use dimension line to measure

I draw line starting from al old line and move the cursor in the diretcion i want till I see 20

Re: autocad precision

Kent1Cooper — Fri, 25 Mar 2022 15:03:33 GMT

@zanetto wrote:

I use dimension line to measure

I draw line starting from al old line and move the cursor in the diretcion i want till I see 20

As already pointed out, the displayed precision of numbers in Dimensions is a part of the Dimension Style definition, independent of the general displayed precision in the UNITS settings.

If you have UNITS displayed precision set to 0 [round to the nearest whole number], then you will "see 20" when the actual distance is anywhere from 19.5 to anything less than 20.5. That would be the cause of your problem.

I suggest you increase your displayed precision setting in UNITS [more decimal places], and draw with SNAP turned on except when there's specific reason to turn it off temporarily. And set SNAP to some value that's at least as large as your UNITS precision setting, e.g. if UNITS must be set to round things to the nearest whole number, set SNAP to at least 1 [but depending on the kind of work you do, you could set it to something like 5 or 10].

Re: autocad precision

zanetto — Fri, 25 Mar 2022 15:12:51 GMT

So I must set units precision to 0 and set snap precision to 1?

How can I change snap precision?

Re: autocad precision

cadffm — Fri, 25 Mar 2022 15:15:49 GMT

Still now DWG from you, why?

We have to guess, instead a quick check what is wrong on your side.

Make sure your sample file is empty or set osnapcoord to 2 (or 1),

before you create the line.

Others ways to check the line length:

Set LUPREC to 8 and use command LIST

or CTRL+1 properties palette

to check the real length.

Possible issue: Your line is not 20 long (possible if you changed osnapcoord to 0)

or your dimstyle has a factor >1

Share a DWG with your line and you get answers

Re: autocad precision

cadffm — Fri, 25 Mar 2022 15:20:56 GMT

"till I SEE"

Thats not the way to make a drawing (except you are using the snap feature).

TYPE IN the values you want!

Read your help about LUPREC and AUPREC,

set it to 8 (highest display precision for menus).

The precision for dimensions you can set up in your DimStyle.

Re: autocad precision

leeminardi — Fri, 25 Mar 2022 15:32:35 GMT

@zanetto

1. The value for "precision" with the units command or in the dimension style dialog box has nothing to do with the precision of the length you get when you create a line. Precision only affects the number of decimal places that you see for the length of the with properties, list and when adding a dimension line.

2. To have lines that you create while freehand clicking points on the screen be rounded to some base value (e.g., 1) you have several tools you can use.

a. Grids. Setting a grid to 1.0 and turning on grid snapping will snap all screen picks to the grid. This is useful primarily when drawing horizontal and vertical lines.

b. If you want to draw a line at a "nice" angle (e.g., 0°, 30°, 60°...) and have a length rounded to the nearest whole number use Polar Tracking with grid snap on the Polar Distance set to 1.0.

Try it!

Re: autocad precision

pendean — Fri, 25 Mar 2022 15:40:05 GMT

@zanetto Here is what we think is going on:
1) you are not actually drawing a line at 20 accurately.
2) your method of measuring the length is incorrect.
3) you appear to be shy about sharing your DWG file to us for some odd reason instead of letting us truly help you so you never do this mistake again (aka you will never learn from your mistake).

How would you like to proceed?

Re: autocad precision

Kent1Cooper — Fri, 25 Mar 2022 17:35:28 GMT

@zanetto wrote:

.... How can I change snap precision?

Read about the SNAP command in Help.

Re: autocad precision

leeminardi — Fri, 25 Mar 2022 18:36:20 GMT

I would not recommend setting the units precision to 0. You want confirmation that the coordinates of a line's ends are where they should be and not rounded off when they are DISPLAYED! Leave the precision at 0.0000.

Learn the use of grids and grid snap as discussed here.

Re: autocad precision

Dhananjai_Gopika — Fri, 25 Mar 2022 22:24:30 GMT

Kindly try the steps mentioned in the link below:

https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/sfdcarticles/sfdcarticles/Linear-dimensions-not-consistent-with-actual-length-of-line.html

Let us know if it helps in resolving the issue.