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drawing a polynomial in Acad...?help? thanks!


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hi guys/gals, i was wondering if it is possible to draw a polynomial of the 4th degree in Autocad and if it is, how would i do this?

 

i was thinking along the lines of nurbs, but i don't know anything about nurbs!

 

thanks in advance, and please respond ASAP if you have the slightest idea!

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If you can calculate x-y points at intervals you can draw an approximation of a polynomial. Using a polyline then fitting the points should give you a curve close enough for practical purposes. A lisp or VBA routine would facilitate this (perform the calculations).

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Guest Academy

that's what i did...i ended up calculating all the radii with respect to the height and just connected the curve.

 

for the curious few, we had to design a duct that would "levitate" a typical raindrop (diam. = .2mm - 5mm) after falling at the speed of each raindrop's terminal velocity and float it there in the duct where the height (y) is a function of the raindrop's diameter. one side of the duct had to be flat for photographical purposes and the other side geometrically shaped to allow the linearity between each raindrop's diameter and it's height at which it "levitates". we ended up using a semicircle for those curious. our raindrops were linearly seperated by a height of .02m for every .2mm diameter change with the 5mm raindrop being at the very bottom (y=0.00m) of the duct and the smaller raindrop, .2mm being at the very top (y=.48m)

 

thanks for the input anyways though :)

 

i also couldn't figure out how not to plot hidden lines...it was pissing me off!

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  • 8 years later...

I'm going for the prize today for the person that brings back a zombie thread with the oldest date. I literally stumbled across this while trying to help another CAD tech with a problem that required a custom lisp routine to solve. It was written by Bill Gilliss on 3/14/2010 and purported to work in AutoCAD 2000 and above.

 

Caveat: No, I did not test it.

 

GraphPolynomial.lsp (GPN) graphs any polynomial equation in the form of

 

y = axn + bxn-1 + cxn-2 ... + dx + e

 

using the origin of the current UCS as 0,0. The equation may be of any degree, i.e., no limit to highest exponent. The equation is both displayed as a text string and assigned to the global symbol GPNequation for use in labeling. Results may be plotted as points, line segments, a polyline, or a spline.

 

Lisp routine removed.

 

Sorry about the above. I just noticed the author asks that lisp routines not be posted to other sites but interested users should instead be directed to his website for the latest version. I shall endeavor to follow his wishes. Find the lisp routine along with a few other interesting ones at...

 

http://www.realerthanreal.com/autolisp/index.html

Edited by ReMark
Removed attached lisp routine
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