Possible to draw a Perfect Circle???......

  • Thread starter Thread starter Brandono
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3-Wheel Drive
"a straight curve on which that passes between any two points, and extends infinitely in either direction."
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Did you write that? Try proof reading it.

A straight curve? In the post from which you quoted me, there is a definition of curve. Read it, and you'll find that it very much contradicts what you've just said.

As for the rest of the definition, the grammar just makes no sense.
 
nic_brix
Why do lines have to have an infinite length VTGT07?

A straight line is simply the shortest distance between any two points.

It can continue infinitely in either direction. In practise it would be impossible (I.M.H.O.) to stop its angle of direction varying when trying to continue it for an infinite distance, thus making it no longer "perfectly" straight.

But the definition of a straight line does not include infinite length.
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This is where you are mistaken. You are thinking of a line segment.

http://mathworld.wolfram.com/Line.html

edit:

3WD beat me to my own rebuttal. Oh well .. lol
 
VTGT07
This is where you are mistaken. You are thinking of a line segment.

http://mathworld.wolfram.com/Line.html
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...Which is what 3-Wheel Drive has just tried to say, but you seem to have done it somewhat better than him.
Anyway, I am prepared to admit that I may have been referring to a line segment, rather than a line.

I decided that I was in a hole, and to stop digging.
In this case I didn't have any evidence to back myself up.
But I believe the rest of that post is still correct.
 
Brandono
I get the whole saying it's impossible […] to draw freehand because you have to be so precise.
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I can draw a perfect circle using Freehand just fine…




It doesn’t look like a perfect circle to you, because your screen only renders bitmaps, but it’s truly a vector object (thus, perfectly circular). And I did it in Freehand (and not even Freehand MX – Freehand 10!).

I win.
 
You would pull that crap Sage.

:lol:
 


I drew a perfect circle.
 
Yep .. I was waiting for that one as well.
 
nic_brix
Did you write that? Try proof reading it.

A straight curve? In the post from which you quoted me, there is a definition of curve. Read it, and you'll find that it very much contradicts what you've just said.

As for the rest of the definition, the grammar just makes no sense.
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Actually, straight curve is in fact a word, it defines a line. A curve is just a series of connected points, they can be connected in any fashion, including a straight line.

As for my grammer, yes, I know it is a bit wordy (but is correct), I just didn't know how to explain it better.

Here's some Wikipedia articles if you are still confused:
[WIKIPEDIA]Line (mathematics)[/WIKIPEDIA]
[WIKIPEDIA]Curve[/WIKIPEDIA]
 
"Straight curve" <-- 2 words.

Whether it makes sense, though, is once again down to where you get your definition from.

Wikipedia says it does make sense:
"Simple examples are the circle or the straight line." (referring to curve)

My trusty old dictionary says it doesn't:
"curve n.
1. a continuously bending line that has no straight parts."
 
spacetime is curved, so if you want a perfect circle, you must account for it.
 
nic_brix
"Straight curve" <-- 2 words.

Whether it makes sense, though, is once again down to where you get your definition from.

Wikipedia says it does make sense:
"Simple examples are the circle or the straight line." (referring to curve)

My trusty old dictionary says it doesn't:
"curve n.
1. a continuously bending line that has no straight parts."
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The dictonary isn't an end-all in definitions, and doesn't always give the most accurate one, especially with subject-specific ones, such as this. For example, the dictionary doesn't have the law of cosines listed.

For a mathematic term, I would trust the definition given by a glossary, like this one (mathwords: curve)

Curve: "A word used to indicate any path, whether actually curved or straight, closed or open. A curve can be on a plane or in three-dimensional space (or n-dimensional space, for that matter). Lines, circles, arcs, parabolas, polygons, and helixes are all types of curves."
 
Who said you can't draw a perfect circle?



The outcome amazed me, I didn't think it could be done like that, or come out that good. :scared:
 
Wow, I remember trying to do that in art class. Never anything that big though. :crazy:
 
Think outside the BOX...er...Circle. To draw the Perfect circle, your pencil should be a fixed point. Rotate the paper from a second fixed point and that would give you a theoretical perfect circle.
 
03R1
Think outside the BOX...er...Circle. To draw the Perfect circle, your pencil should be a fixed point. Rotate the paper from a second fixed point and that would give you a theoretical perfect circle.
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The pencil would create a line with varying thickness. You'd need a pencil with infinitesimal contact with the paper, creating a prefect line with infinitesimal thickness.

Start from the very beginnings of the problem. Before you draw a perfect circle, you have to figure out how to draw a perfect anything. A perfect line, a perfect point. The best drawing mechanism I can think of is a beam of laser light, but even that has problems.
 
I think it's impossible to draw a perfect circle. A perfect circle is a mathematical expression, and the shape merely a representation. Any circlular shape you've ever seen is only an imperfect representaion of a perfect mathematical expression. A perfect, physical circle may exist somewhere in the universe, but not on Earth.

And, as Danoff says, it's tough to draw a perfect anything. THe definition of a square, for example, is perfect, but no visible square is has ever been perfect.
 
Danoff
The pencil would create a line with varying thickness. You'd need a pencil with infinitesimal contact with the paper, creating a prefect line with infinitesimal thickness.
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I see what your saying. So it depends on your measurement criteria is. If you are measuring from the centerline of the Pencil it wouldn't matter what width the line is. Your discribing the inside or outside diameter of the circle, thus needing different media to determine your work point. I believe that a perfect circle is possible because it should be defined as the constant diameter dimension which is possible to create and verify with current technology.
 
How do you calculate the centerline?
 
Exactly. I could draw you a circle right now with a marker and tell you that somewhere in the middle, the centerline is perfect. So much for the &#8220;center&#8221; part.
 
But only if your circle is perfectly round. If it isn't round, then there's no center point that would measure equally to all points on the circle's circumference. But even if it was in the perfect center of your perfect circle, there's no way to physically measure prefectly. The only way to "measure" that tightly is with math, which can't necessarily be shown physically.


And O3R1, the only way to verify if your measurements might be correct is through mathematics. But there's no way to know where to start, because there's no way to accurately measure a starting point by physical means. My father's machines can cut metals to tolerances of a couple ten-thousandths of an inch. Truthfully, that's not very accurate by anyones calculator. You can still feel elevation changes at that tolerance, and that's as close as most machines can measure these days. You could use a laser, because the laser itself is almost perfectly accurate, but the machine that holds the laser won't be able to hold a position much tighter than a couple ten-thousandths of an inch.
 
Anything mathematical is imaginary, while reality consists of useful approximations. It's easy enough to comprehend the set of points that portray a circle, but putting them in real life is always approximate down to 2, 3, maybe 4 decimals with good stuff.

You can't draw a PERFECT circle, but you can draw one that is indistinguishable from perfect by any reasonable measurement. If the piston goes up and down the cylinder at an average 3500 times a minute for 150,000 miles, then the circular approximation is adequate.
 
I like that explanation, wfooshee. Math is imaginary, but we are real. Therein lies the problem.
 
Danoff
How do you calculate the centerline?
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It would be the distance from the two work points that I discribed earlier. The mark left on the paper by the pencil lead is irrelevant.

I don't care if it has a bazillion zeros after it...as long as you have TWO fixed points...a perfect circle can be accomplished. Then the diameter of the circle will equal two bazillion. Its not as complicated as you guys are trying to make it.
 
SRV2LOW4ME
Who said you can't draw a perfect circle?



The outcome amazed me, I didn't think it could be done like that, or come out that good. :scared:
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i dont care if its perfect, that was amazing !!!
 
03R1
It would be the distance from the two work points that I discribed earlier. The mark left on the paper by the pencil lead is irrelevant.
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You're describing a theoretical circle, not the one you drew.
 
Danoff
You're describing a theoretical circle, not the one you drew.
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There are machines on this planet that can start, rotate and end without losing any measurable tolerance. What more do you want then that? To talk about a number that none of us can fathom or put to practial use.
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If the main question is could the human hand draw a perfect circle I would agree that the answer is no.
 
03R1
There are machines on this planet that can start, rotate and end without losing any measurable tolerance. What more do you want then that? To talk about a number that none of us can fathom or put to practial use.
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If the main question is could the human hand draw a perfect circle I would agree that the answer is no.
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The question is whether a perfect circle can be drawn at all. Rotating a piece of paper makes a circle, but the line drawn is imperfect. It has width and irregularities. If you want to talk about a theoretical centerline of the mark you've made, you're talking about a theoretical circle that doesn't exist in reality. The circle you drew has irregularities and imperfections.

Again, the circle isn't the problem. The problem is that no line can be drawn perfectly.
 
Danoff
Again, the circle isn't the problem. The problem is that no line can be drawn perfectly.
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It seems like you are stuck with the pencil and paper media. What if it was a laser cut piece of steel? Could that accomplish a perfect circle?
 
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