Line style for parts of an ellipse

Joscha_1607 shared this question 1 year ago
Answered

Hey everyone,

I am currently trying to reproduce a figure that is presented in this paper. I created a sphere as a 3d figure and projected it onto a 2d plane (see attachment). Now I want to change the line style of the "invisible" part of the 2d projection to make it look similar to the 3d case. The paper tells me to use the intersection tool but I have no idea how that helps me to proceed. Any help is greatly appreciated.

Cheers,

Joscha

Best Answer
photo

change style of ellipse to doted

place 2 point on ellipse

create Arc(<ellipse>,<point1>,<point2>)

adjust the 2 points to the "horizont"

see red sample in attachment

Comments (2)

photo
1

So I came up with a working but rather unsatisfying solution that involves splines. One can just add a few points along the projected circles and then use two splines to recreate the visible and "invisible" sections. It is however quite tedious and time consuming. I also noticed that the "Section( <conic>, P1,P2)" command does pretty much what I need.

Is there a possibility to redraw the curves like the "Section" command does without actually enclosing the defined section (something similar to the Circumcircular Arc command just for conic)? If it is possible, how do I do it? I attached my .ggb file if someone wants to take a look.

photo
1

change style of ellipse to doted

place 2 point on ellipse

create Arc(<ellipse>,<point1>,<point2>)

adjust the 2 points to the "horizont"

see red sample in attachment

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