Protractor tool does not showing precise angle


#1

Hi,
When I measure angle with Protractor tool, it show me incorrect number.
For example, the angle is exactly 37 degrees, but Protractor shows me 37,4.
When I draw the same object in AutoCAD, it shows me correct 37.

Why is this happening?

Thank you


#2

I get 37.405°
Perhaps you should check the settings in your “other” CAD app.

Shep


#3

I try in AutoCAD and DraftSight, this is correct:

I also transfer the same object in Sketchup Layout and Layout shows exactly 37, not 37,4.
It’s something with Sketchup.


#4

Set your AUPREC variable in AutoCad to 3, for instance - you seem to have it at 0. My calculator gives 37.40535663

It is about your unit display precision settings.

Anssi


#5

OK, thank’s Shep and Anssi, you two are correct.
I change settings in AutoCad and now I get 37,4, so Sketchup is showing correct angle.


#6

This is one of those threads that should be shown to all the people that think the “Proper Software” is accurate and sketchup is only for inaccurate hobbyists.


#7

that’s just user error though :wink:


#8

That’s the thing about tools … They’re all pretty much useless without a skilled operator.
CadStd Pro $37.50 ($25 back in the day)


#9

So far so good, but can we trust SketchUp on being accurate here? The shown angle is only in 3 decimals while the lengts may be displayed in up to six decimals.

Little test (only for this case!, but still,) with the help of Excel to see if the protractor does accept more than 3 decimals to see if I should trust SketchUp.
Precision in displaying lengths set to 0.000000mm

base 34000mm --> protractor angle input 37° --> height 25620,837703mm
base 34000mm --> protractor angle input 37.4° --> 25994,962853mm
34000mm --> 37.405° --> 25999,664617mm
34000mm --> 37.4053566° --> 25999,999970mm
34000mm --> 37.40535663° --> 25999,999999mm
34000mm --> 37.405356631° --> 26000,000000mm

(scaled up 100x to continue checking the protractor angle input)
3400000mm --> 37.405356631° --> 2599999,999962mm
3400000mm --> 37.405356631408° -->2600000,000000mm

It seems that the protractor accepts far more than 3 decimals.
Unfortunately though, SU only shows 3 decimals.
But I think I can trust SketchUp’s accuracy on this one.


#10

some more numbers… i was curious to see what .001º looks like in a scenario i can picture in my head. (because in any practical application i use, i can’t imagine a scenario of being able to tell the difference between 0º and .001º)

so… a line 100m long (roughly a football field)
1º rotation is 1.7453m error
.001 = 1.7453mm
.00001= .0175mm
etc.

if throwing a dart to the moon from earth ( :joy_cat: ) and your aim is off by .001º ,you will miss your target by ~4 miles.

(using 238,900 miles as distance from earth to moon)