# [CST-MWS] How to get data-points for 2D geometry?

1. ## [CST-MWS] How to get data-points for 2D geometry?

Dear Members
Good day to you.

I have the following elliptical shape in CST-MWS. How can I export the complete set of XY date-points for the design rather than the highlighted four points. Best Regards •

2. ## Re: [CST-MWS] How to get data-points for 2D geometry?

To send only the outline:

1) Send a code which designates row 1.
2) Starting from the left, send column position of each pixel which is turned on.
3) Do the same until you reach the rightmost pixel which is turned on.
4) Your receiving software understands to turn on each pixel listed (not pixels in between).
5) Send a code which designates 'next row'.
6) Etc. Continue to last row of image.

To send the entire blue area:
1) Starting at row 1, send column position of leftmost pixel which is turned on.
2) Send column position of rightmost pixel which is turned on.
3) Your receiving routine 'understands' that all pixels in between are turned on.
4) Continue likewise for all rows. •

3. ## Re: [CST-MWS] How to get data-points for 2D geometry?

you have the "vertices" of the ellipse - that is the four points

the major axis is the horizontal distance from the left point to the right point. (27)
the minor axis is the vertical distance from the top point to the bottom point. (13)

now it gets interesting:
the semi major axis and the semiminor axis are 1/2 respectively, or a = 13.5 and b = 6.5

the eccentricity is e = square root ( 1 - (b/a)^2 ) or 0.87645

https://en.wikipedia.org/wiki/Ellipse

look for da La Hires method of drawing ellipses

basically x = a cos (theta) and y = b sin (theta), for theta = 0 to 360 degrees
so you can construct the ellipse outline mathematically with as many points as you like •

4. ## Re: [CST-MWS] How to get data-points for 2D geometry?

supplement:

a point x,y is inside the ellipse if y < b sin (tan inverse (y/x)) AND x < a cos (tan inverse (y/x))

if y = b sin (tan inverse (y/x)) AND x = a cos (tan inverse (y/x)) then x,y is on the ellipse

and if y > b sin (tan inverse (y/x)) OR x > a cos (tan inverse (y/x)) then x,y is outside the ellipse 5. ## Re: [CST-MWS] How to get data-points for 2D geometry? 