Help with Ellipses

[Khughes222]

I need some help understanding how to determine your "reference points" and string length for drawing ellipses.

I like the grumman 2 style but I want to modify the design to be 54" tall instead of 48". Given the current reference points, if I just raise them 6" I dont get the same ellipse style that the original has. Something else needs to change. I just dont know what it is.

Is there a specific formula for figuring out reference points for ellipses?

Thanks,

[aggie79]

Are you using the grid reference dimensions in the design library? If so, and if you are only altering the height and not the length, then instead of a 3" vertical grid spacing, the vertical grid spacing would be 54"/48" x 3.375" (3-3/8"). The horizontal grid spacing would still be 3".

[Khughes222]

Are you using the grid reference dimensions in the design library? If so, and if you are only altering the height and not the length, then instead of a 3" vertical grid spacing, the vertical grid spacing would be 54"/48" x 3.375" (3-3/8"). The horizontal grid spacing would still be 3".

Never tried the grid spacing because my understanding of it never clicked with me until just now. Im still interested to know though how to determine the reference points to create the ellipse. I have googled everywhere and there is plenty of information on drawing ellipses, but they never talk about where they actually came up with the exact details of where the reference points and string length need to be.

Thanks,

[mikeschn]

to determine string points read here: http://www.mathopenref.com/ellipsefoci.html

or google foci.

Mike...

[Fishingtomatoseed]

Hope this helps.......

[Fishingtomatoseed]

Here is another page showing the ellipse. From Mike's posted web site.

http://www.mathopenref.com/constellipsefoci.html

[angib]

This isn't as simple as it looks, if you're going to keep the front and back bottom curves as simple circular arcs.

And others might want the same information, so here's a custom profile for you - download the PDF below.



http://www.angib.pwp.blueyonder.co.uk/t ... .5high.pdf