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Errors in drawing precision

Anonymous

Errors in drawing precision

Anonymous
No aplicable

Hello bloggers, 

 

I'm a user of Autocad 2016 and I'm having trouble with the precision of the drawings. I always use Polar (F10) and Object Snap (F3) and I've been doing it like this since I started using Autocad 8 years ago and I've just started now to have this problem.

 

The thing is that when I give distances to my drawings I always do it in precise number, for example 1 m, and once the line is drawed I check the distance and it says 0.9999 m. If it was just once is not that horrible, the thing is that with this mistakes I start dragging mistakes until its too big. 

 

Anyone can tell me why this happens? Is there anything I could do to fix it?

 

Thanks a lot.

Responder
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18 Respuestas
Respuestas (18)

ennujozlagam
Mentor
Mentor

hello, you can try to check it HERE, previous thread some discussion. thanks





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imadHabash
Mentor
Mentor

Hi,

would you please attache here a CAD .dwg sample that describe your issue , for checking some settings and other issues ? 

 

Regards,

Imad Habash

EESignature

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Anonymous
No aplicable

Sure! Here it goes. 

 

This line was made as a copy at 1m distance of the original line (the wall) when I use the Distance comand with the polar referece it says 0.9999, as you can see in the image. Hombre frustrado

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cadffm
Consultant
Consultant

That isn't a dwg, it's only a stupid Picture where we can not check the object properties.

Sebastian

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imadHabash
Mentor
Mentor

sorry ... we need the drawing itself ( just a little information in it ) not an image !! 

EDIT : from your first post .....

>> I'm a user of Autocad 2016 and I'm having trouble with the precision of the drawings. <<

your image shows that you use AutoCAD 2017 !!!

Imad Habash

EESignature

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Anonymous
No aplicable

Sorry, my mistake, I recently changed to Cad2017 and I forgot. Here I attach you a part of te problematic drawing.

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imadHabash
Mentor
Mentor

Hi,

i'll give a reply for the same drawing location that you show it in your previous image ... as seen from below image and if you draw a horizontal line ( Magenta color ) you will find that you have a non horizontal oblique line when you zoom in , so i suggest to modify it well and be careful when you select your objects with osnap modes , try to use two or three osnap modes to avoid such a problems . also review that hatch which need more accuracy to fit all the space in correct way . 

vvv.png

 

Imad Habash

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Anonymous
No aplicable

I know, I've checked the horizontality of the line first thing. The problem is that this line was made with the Polar from an original horizontal line (already checked that too) , which lead me to this mistake. So I realized that the problem of accuracy is withing the Polar mode. It's not just one mistake, I've seen it repeatedly in different parts of the drawing, and always with lines drawn with te Polar mode ON. 

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imadHabash
Mentor
Mentor

>> So I realized that the problem of accuracy is withing the Polar mode. <<

polar tracking is work depending on your current cad elements accuracy . so i doubt if you have right and well done elements that you will get out with such a problem . :cara_guiñando_un_ojo:

 

Regards,

Imad Habash

EESignature

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Alfred.NESWADBA
Consultant
Consultant

Hi,

 

>> The problem is that this line was made with the Polar from an original horizontal line

Just as one idea ... have you ever used the express tools command SYSVDLG to import settings?

(either in that drawing or in the template you started with .. or was the drawing created by anyone else).

Reason: exporting and importing settings makes sysvars about angles <> 0° inaccurate.

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2025
------------------------------------------------------------------------------------

(not an Autodesk consultant)

cadffm
Consultant
Consultant

I can not understand because your DWG (according to your image section) has neither 0.99999999 nor 1.0000000.

The distance is = 0.79986112 and that shows me Polartrack too.

Assuming the distance is actually 1m, then 0.9999 is often explainable by a problem with the number of digits and the rounding, a mathematical story.

_PER calculates a certain point, and if you have to round off the calculation, then there may be minor deviations.

But in your DWG the length is not 1 but 0.79986112, so probably a bad example and does not fit to your picture !?

Sebastian

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ChicagoLooper
Mentor
Mentor

I think you are confusing F10 with F8. Using polar tracking (F10) will not necessarily give you a horizontal or vertical line. To do that you need to use F8, ORTHOMODE, which restricts the cursor to move only horizontally or vertically relative to the UCS. When you combine F10 with snap (F3) you may, in some cases, be drawing a line at an angle, or with slope.

 

You are using DIMLINEAR which does not account for an 'angled' line so your distances will be inaccurate. You may, however, use DIMALIGNED to make your dims parallel to your target object. Your issue is not your drawing object. Your issue is using of F10 instead of F8.

Chicagolooper

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neaton
Advisor
Advisor

@Alfred.NESWADBA- Do you have more information on SVSVDLG? I haven't heard of this problem before.


@Alfred.NESWADBA wrote:

Hi,

 

>> The problem is that this line was made with the Polar from an original horizontal line

Just as one idea ... have you ever used the express tools command SYSVDLG to import settings?

(either in that drawing or in the template you started with .. or was the drawing created by anyone else).

Reason: exporting and importing settings makes sysvars about angles <> 0° inaccurate.

 

- alfred -




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Alfred.NESWADBA
Consultant
Consultant

Hi,

 

>> Do you have more information on SVSVDLG? I haven't

>> heard of this problem before.

SYSVDLG only exports values with the number of digits set in the UNITS dialog.

Now let's run a sample with an angle of 90° and just two decimal places while exporting:

 

AutoCAD calculate all angles in Radiant, which means 90° = 1.5707963268r (rounded to 10 digits)

When exporting a value of 90° with 2 digits the value 1.57 will be exported.

When importing that value of 1.57 you get as result 89.9544° which is not any more exactly 90°

 

This happens to all angles in your setvar which are not 0.000

 

20180626_151344.png

 

At least the same problem exists with length values as they are also rounded, especially when values were converted from metric to imperial or vice versa (e.g. linetype distances), but angle is imho the most critical one.

 

That's why I use SYSVDLG quite often just to have the option to compare drawing settings, but I never ever import these settings back into a drawing.

 

Hope that is clear, if not feel free to ask :cara_guiñando_un_ojo:

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2025
------------------------------------------------------------------------------------

(not an Autodesk consultant)

Anonymous
No aplicable

These all seem really silly/irrelevant comments to a straightforward AutoCAD question. Can a moderator please qualify:

Q: If a line is command-specified as 1, with a drawing precision of 0.0000, why does annotation shows as 0.9999?

No other CAD software requires this correction: what does AutoCAD need to correct this error? 

 

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cadffm
Consultant
Consultant

A moderator has nothing to do with your software, a moderator moderate a board.

 

You should start to read, learn and understand the comments, they are not silly or irrelevant.

 

And all CAD Software like Autocad has the same problem, perhaps some software hides it more.

 

>"what does AutoCAD need to correct this error"

First we need to know what the "error" is, because there isn't "the one and only on'the error'

 

I guess you are drawing far away from 0,0,0 WCS? Try it at 0,0,0 WCS, same problem?

 

>"why does annotation shows as 0.9999?"

What does it mean, the simple dynamic mode information near to the cursor?

 

>"with a drawing precision of 0.0000, why does "

Are talking about LUPREC or what does it mean?

 

-

 

Again: There isn't "the one Problem", if you want to know detail we need to know the problem. Upload the dwg, share screencast to show what you do and talked about.

 

It sounds the line isn't 1.0 long

Sebastian

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Alfred.NESWADBA
Consultant
Consultant

Hi,

 

>> These all seem really silly/irrelevant comments

My reply was an answer to @neaton 's post 14 where he asked me about more information to SYSVDLG.

I don't know why you see my post as silly ...

 

- alfred -

PS: good introduction to a forum with such wording in your first post

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2025
------------------------------------------------------------------------------------

(not an Autodesk consultant)
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RobDraw
Mentor
Mentor

Unless, as mentioned before, you are extremely far away from the origin (a known issue), this is due to user error.


Rob

Drafting is a breeze and Revit doesn't always work the way you think it should.
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