How To Draw This 2D Curve?

[spinecad]

Can anyone be able to draw the curve similar with such as the attached image in AutoCAD 2012/2013?

 

If yes, can you please show it to me?

 

Thank you

[SEANT]

The curve looks parabolic.

 

Draw a horizontal line from A to the right. Draw a vertical line up from B. Fillet (Radius = 0} the lines to form a corner.

 

Start the SPLINE command, Method=CV, Degree=2. Snap to A, the filleted corner, then B.

[Guest AARi]

... also seems 1/4 ellipsoid xy+

 

% matlab

a=00.01;

b=0.005;

L=3;

x1=linspace(0,L/3)

x2=linspace(L/3,L)

u1=-a*ones(size(x1))

u2=3*a-(((b^2)/a)*(x2.^2))

x=[x1,x2]

u=[u1,u2]

area(u,'Displayname','u');figure(gcf)

xlabel('x')

ylabel('u(x)')

% end

 

have fun

[neophoible]

Well, I was leaning toward a parabolic path, but even it does not seem to be a perfect fit. It looks like a non-ideal trajectory, but still very closely approximated by a parabola. In the figure, I superimposed an elliptical section in green and a parabolic section in red. Obviously, I could not be precise, as the image is imprecise. Still, this should be close enough to get the idea. Note that "ellipsoidal" refers to 3D, not 2D.

[neophoible]

... also seems 1/4 ellipsoid xy+

Were you suggesting that your posted code can be applied directly to AutoCAD? If so, how? Also, if you consider the posted path to be elliptical, why would you not just recommend the Ellipse command?

[Guest AARi]

 

..well you can use bezier curve, splines, ellips... commands in AutoCad

or use a specific math soft. to draw functions

 

MatLab, Octave or SciLab.. then import into autocad as imag and redraw it

.... Octave or SciLab are open sources.

 

let me some time to study optional modulus to xport/import as .dxf into autocad

and.. may be someone can write a script directly

Edited May 8, 2013 by AARi

[spinecad]

Does parabolic curve will perfect fit as my attached image?

[Guest AARi]

spincad...

there are curves functions as stars in the sky

have a look this one y=f(x)=-h*((x/b)^2)

or [n>0] y=f(x)=-h*((x/b)^n)

..

if you have at least a three points of the curve (see coordinates x-y), then calculate if all three fit the equation function

so this will be the function than you are looking for..

 

they are not linear function,they are cuadratic or cubic or..or... curves

should be better if you let me know for what you need that curve (is something aprox. or have to be something exactly like representation of strain, strees, axial forces, road slope.....)

 

SciLab is free soft. [150mb]. And suppose, have to be a portable version

Edited May 8, 2013 by AARi
updates

[spinecad]

The curve looks parabolic.

 

Draw a horizontal line from A to the right. Draw a vertical line up from B. Fillet (Radius = 0} the lines to form a corner.

 

Start the SPLINE command, Method=CV, Degree=2. Snap to A, the filleted corner, then B.

 

It is a quadratic Bezier curve and it does not prefect fit.

[SEANT]

It is a quadratic Bezier curve and it does not prefect fit.

Correct. Though the fit is pretty close.

 

If you need something closer use a FIT spline with as many points as necessary.

[neophoible]

Correct. Though the fit is pretty close.

 

If you need something closer use a FIT spline with as many points as necessary.

Sounds right. And shouldn't this method work for any curve he wishes to draw?

[SEANT]

Yes. If a curve is not linear or circular, a FIT spline is a good choice.