spinecad Posted April 27, 2013 Share Posted April 27, 2013 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 Quote Link to comment Share on other sites More sharing options...
SEANT Posted April 27, 2013 Share Posted April 27, 2013 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. Quote Link to comment Share on other sites More sharing options...
Guest AARi Posted April 30, 2013 Share Posted April 30, 2013 ... 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 Quote Link to comment Share on other sites More sharing options...
neophoible Posted May 1, 2013 Share Posted May 1, 2013 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. Quote Link to comment Share on other sites More sharing options...
neophoible Posted May 1, 2013 Share Posted May 1, 2013 ... 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? Quote Link to comment Share on other sites More sharing options...
Guest AARi Posted May 8, 2013 Share Posted May 8, 2013 (edited) ..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 Quote Link to comment Share on other sites More sharing options...
spinecad Posted May 8, 2013 Author Share Posted May 8, 2013 Does parabolic curve will perfect fit as my attached image? Quote Link to comment Share on other sites More sharing options...
Guest AARi Posted May 8, 2013 Share Posted May 8, 2013 (edited) 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 Quote Link to comment Share on other sites More sharing options...
spinecad Posted May 9, 2013 Author Share Posted May 9, 2013 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. Quote Link to comment Share on other sites More sharing options...
SEANT Posted May 9, 2013 Share Posted May 9, 2013 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. Quote Link to comment Share on other sites More sharing options...
neophoible Posted May 10, 2013 Share Posted May 10, 2013 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? Quote Link to comment Share on other sites More sharing options...
SEANT Posted May 10, 2013 Share Posted May 10, 2013 Yes. If a curve is not linear or circular, a FIT spline is a good choice. Quote Link to comment Share on other sites More sharing options...
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