Mathematical error in CAD?
Printed From: CAD Forum
Category: EN
Forum Name: Civil 3D, Map, InfraWorks
Forum Description: Discussion about mapping and GIS applications Map, Civil3D, InfraWorks, MapGuide and Raster Design
URL: https://www.cadforum.cz/forum_en/forum_posts.asp?TID=12707
Printed Date: 11.May.2026 at 21:25
Topic: Mathematical error in CAD?
Posted By: KingsDaughter
Subject: Mathematical error in CAD?
Date Posted: 18.Apr.2018 at 19:03
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I have a triangle shaped area of property. In labeling the lines, CAD gives an incorrect answer for the hypotenuse of the triangle. It should be 73.85 and CAD shows it as 73.997. What's up with that and is there a setting I need to change to get the correct length?  ------------- God Loves You |
Replies:
Posted By: Kent Cooper
Date Posted: 18.Apr.2018 at 19:36
| That would be about right if it were a right triangle, but the other two edges are not perpendicular to each other. |
Posted By: KingsDaughter
Date Posted: 18.Apr.2018 at 19:48
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Good catch, Kent Cooper! I changed the decimal setting and discovered the angle is 90.314. Thank you! Sometimes you just need more eyes on the problem to see it.  ------------- God Loves You |
Posted By: Kent Cooper
Date Posted: 18.Apr.2018 at 20:42
| You can see it without having to draw an angular Dimension. In that kind of situation, depending on the specific directions, the degrees-minutes-seconds parts of the metes and bounds for two lines would have to have either their sum or their difference equal to 90 degrees for them to be perpendicular. Just looking at the sum of the degrees and minutes parts for that triangle's legs, you get only to 89 degrees 40 minutes. The seconds adds about another arc-minute, but the total is clearly not going to be 90 degrees. |
Posted By: Kent Cooper
Date Posted: 19.Apr.2018 at 18:36
[I just realized I was wrong about that -- it's only the sum. Surveyor's Units D-M-S values never reach or exceed 90 degrees.]
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Kent Cooper wrote:Posted By: mypushpi
Date Posted: 18.Oct.2018 at 11:01
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The values of lengths and angles which displaying in drawing are not right accurate. there are some digits remaining, but not displaying in our parameter. so it is very close to, but not equal to value. Answers depend on accuracy. ------------- Pushpika |
Posted By: Kent Cooper
Date Posted: 18.Oct.2018 at 19:09
It knows accurately -- you probably just have it set to display rounded off to a lower precision [fewer decimal places, or lower-denominator fractions] than you want. Look into the LUPREC and AUPREC System Variables, and in Dimension Styles, the Primery Units' Precision settings for both Linear and Angular Dimensions.
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