That's an awesome easy way. I am just curious, how accurate is that parabola? The specified points should be correct, but the spline curve automatically chosen by AutoCAD BETWEEN the points are not exactly parabolic necessarily?
Good day Charles for this method of parabola construction the main focus is on the steps that are used to construct the parabola. Once the steps are correct then the spline in AutoCAD will give you a fairly accurate parabola. To get the parabola to be more accurate you can use more division lines between the axial length and span so you get more points.
Good day. The reason for using those numbers is that the span has to be divided into twice the number of parts as the axial length, hence 8 and 4. It could have been 10 and 5 or 16 and 8 and so on but 8 and 4 is easier to deal with as it has less lines. Anything smaller that that such as 4 and 2 though they could be used would not have enough points to plot the curve neatly.
Ensure object snap is turned on and ensure that you have node turned on in object snap in order to draw lines from the points. If you are not seeing the division points type DDP, click on DDPTYPE and then select a DDPTYPE and click ok.
