snap-precision

Hallo Autosketch-Fans

I have AS 6 and there is following problem:
I draw 2 circles and snap the point of intersection,
but the snappoint is'nt precise.
I always have to zoom in and and correct the
snap-point!

Has anybody the same problem?

Is this problem corrected in version 9 (then i
would buy AS 9)

Thank you for your answers and
friendly regards from austria
-- Adi --

 

Hi,
Change to Quadrant mode next time; type Q. Draw the two circles separatly, then type Q and use the ordinary movecomands. The snappoint is then absolutely precise.

 

You need to zoom in real close to see it but you are correct. Version 9
has similar results.

 

Can I make a pedantic comment?

No?

Too bad for y'all, here it is:

Precise doesn't mean the same thing as accurate. They're used interchangeably and
that ain't right.

Neither is ain't, so sue me.

Precision (or the act of being precise) refers to reproducibility, accurate (or
accuracy) refers to the *correct* value as measured by other independent means.

An archer can be precise but not ever hit the bullseye, the correct placement.

What you're all saying is that the AS snap may be precise (if even that), but it's
not accurate.

For a cad program to do that is reprehensible, no?

I never had this problem with etchasketch.

 

Precise doesn't mean the same thing as accurate. They're used
interchangeably and

But in some cases the unprecision was so big,
that after 30 or 40 dependent drawings the
error was visible with free eye!

This was the reason i'd asked!

If I find the sample, I will give you the
coordinates of the circles, where the
difference to precision is nearby 1 mm
and this is too much!

with kind regards
-- Adi --

 

Yes, Adolf, good. When you find the culprit, zip it up and attach it here to a new
post in the newsgroup. I for one would be interested. I've never heard this
particular comment before.

I'm wondering now if you have a grid snap active and are hitting *that* as the
snap point every once in a while. Or maybe there's some other snap causing the
interference.

It would seem to me, knowing nothing about how the algorhythm is written so I
speak from utter ignorance (blissful, too), snaps are so clearly defined logically
that it's impossible for the program to misinterpret them.

Anyone else have a thought here? Ric, John, Paul, Angry, Rod?

H, bemused.

 

No wonder you're bemused Harvey.....you have the terminology all
arse-about-face......!!!!

accurate (or
accuracy) refers to the *correct* value as measured by other independent
means."<

Accuracy refers to reproducibility....precision refers to the correct value
by other independent means.

placement."<

A pilot can be accurate by landing his aircraft anywhere on the field. A
pilot can be precise by landing his aircraft on the runway.

CAD plans can always be accurate.....but not always precise.

That's MY only thought right now.....far too busy converting inaccurate
drawings into precise drawings....!!!!

Ric Norris.
http://users.bigpond.net.au/cavedrawings

 

Accuracy refers to reproducibility....precision refers to the correct value

As crypto-scientists (and in a previous life I was a real one), we should be more
careful in their use.

Here a site that uses the boiling point of water as the experiment:

http://nobel.scas.bcit.ca/chem0010/unit1/1.5_precisionAccuracy.htm

I suspect that in the etymological sense these two words have become confused or
conflated, too bad. If M-W defines them as the same, half the sentient world would
bristle I'd bet.

"Onelook" says that precision is the quality of being reproducible in amount or
performance. Accuracy is the quality of nearness to the truth or the true value.
Sounds right to me.

Looking at M-W...

Wait a sec! M-W says that accuracy "is freedom from mistake or error:
CORRECTNESS." Precision "is the quality or state of being precise: EXACTNESS."

Geez that's awful. Their second definition for each word confuses the two and
actually asks the user to compare the two! Funny, never bothered to look that up.
I believe they've missed the boat, certainly as far as clarity is concerned,
although the scientific usage is indicated in a pompous way.

Hunh. Live and learn, but not much.

 

I do remember this discussion years ago in college. The link you list
is correct. Precision is how close together your result are. Accuracy
is how close they are to the real answer.

But how come the intersection point of the two circles is not selected
properly (it is not accurate)? drafix's method for getting the correct
intersection did not work for me.

Should this be listed as a bug?