ebjco Posted November 29, 2005 Share Posted November 29, 2005 Hi Guys, I am looking for help or directions to a tutorial that can show me how to draw a Parabolic for a Microwave Antanna using AutoCad 2004. Thanks Ernie Quote Link to comment Share on other sites More sharing options...
David Bethel Posted November 29, 2005 Share Posted November 29, 2005 Here's an interesting discussion of curves in AutoCAD http://discussion.autodesk.com/thread.jspa?messageID=1206419 It can be quite a daunting task. -David Quote Link to comment Share on other sites More sharing options...
Squirreldip Posted November 29, 2005 Share Posted November 29, 2005 Roadway vertical curves are parabolic... Here's (basically) how Land Desktop draws vertical curves: First, draw a polyline with two line segments, say from -1,1 to 0,0 to 1,1. Second, set SPLINETYPE to 5 (Quadratic B-spline) Third, set SPLINESEGS to 65 (or higher if you need more segments) Last, PEDIT the polyline and Spline... (Of course you'll need to play with the actual coordinates of the polyline) Not really knowing where you want to go from here... Change your UCS - orthoGraphic to Front then enter PLAN. Array the parabola polar and change your UCS back to world... Quote Link to comment Share on other sites More sharing options...
fuccaro Posted November 30, 2005 Share Posted November 30, 2005 For more control I would use the exact formula. Here is how: ;draw a parabolic solid ; Miklos Fuccaro [email="mfuccaro@hotmail.com"]mfuccaro@hotmail.com[/email] ; Nov. 2005 ; (defun c:parabola( / p dx x rep osmode) (setq p (getdist "\nY+SQRT(2*p*x)\t P=") dx 0.1 ;increment in X direction rep 50 ;repetitions x (- dx) ) (if p (progn (setq osmode (getvar "OSMODE")) (setvar "OSMODE" 0) (command "PLINE") (repeat rep (command (list (setq x (+ x dx)) (sqrt (* 2 p x)))) ) (command (list (* (1- rep) dx) 0) "c") (command "revolve" "l" "" "x" "") (setvar "OSMODE" osmode) ) (princ "nothing to do!") ) (princ) ) Quote Link to comment Share on other sites More sharing options...
anjali Posted June 2, 2009 Share Posted June 2, 2009 i didnot understand the formula can u plz specify what exactly p specify if we want to draw a parabola of width 14 focus 3.5 then what is the value of p? in the above mentioned formula. Quote Link to comment Share on other sites More sharing options...
fuccaro Posted June 2, 2009 Share Posted June 2, 2009 While I was in school I learnt that the equation of the parabola is Y=SQRT(2PX) SQRT means square root. This is the equation I used to draw the solid in the image above. I would say, it looks like a parabola Let me find a book and I will get back. Oh, and welcome in the forum! Quote Link to comment Share on other sites More sharing options...
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