[Answered] Perimeter of an ellipse

Drop in here to discuss whatever you want.

Moderator: andrew

Forum rules

Always indicate your operating system and QCAD version.

Attach drawing files and screenshots.

Post one question per topic.

Post Reply
Panchdara
Premier Member
Posts: 185
Joined: Wed Nov 25, 2015 4:15 pm

[Answered] Perimeter of an ellipse

Post by Panchdara » Sat Sep 05, 2020 8:29 pm

Question: I just watched a neat video on the perimeter length of an ellipse. What formula/approximation does QCAD use?

Best
Last edited by Panchdara on Sun Sep 06, 2020 9:09 am, edited 1 time in total.
Windows 10

CVH
Premier Member
Posts: 3416
Joined: Wed Sep 27, 2017 4:17 pm

Re: Perimeter of and ellipse

Post by CVH » Sat Sep 05, 2020 8:51 pm

Hi,
Ellipse are indeed the tougher ones among the entities.
There aren't closed form solutions.
Talking about perimeter length, what about the others properties ... :wink:
Intersections ... Point on ...

Well, I would not know.
Andrew can tell you that.

So, I keep lurking. :wink:

Regards,
CVH

User avatar
andrew
Site Admin
Posts: 9037
Joined: Fri Mar 30, 2007 6:07 am

Re: Perimeter of and ellipse

Post by andrew » Sat Sep 05, 2020 9:03 pm

QCAD uses Simpson's Rule as approximation for ellipse arc lengths.

CVH
Premier Member
Posts: 3416
Joined: Wed Sep 27, 2017 4:17 pm

Re: Perimeter of and ellipse

Post by CVH » Sun Sep 06, 2020 6:01 am

Thankx
CVH

Panchdara
Premier Member
Posts: 185
Joined: Wed Nov 25, 2015 4:15 pm

Re: [Answered] Perimeter of an ellipse

Post by Panchdara » Sun Sep 06, 2020 9:16 am

Yes, thanks Andrew. Number of iterations? Or is that dependent on particular setup/specifics of the drawing (such as ellipse ratio)? (I think if I tried to read the code, it'd be like looking for a needle in a haystack :D )

I am just curious as I had just watched an entertaining video on the subject.

Best regards
Hugh
Windows 10

Post Reply

Return to “Chat”