Many-point curve-curve intersection

Leo shared this question 3 months ago

Hello, I have a stationary curve and the one depending on a parameter with a slider.

I need the program to show all the intersections of the curves and, preferably, automatically calculate the number of the intersections. However, when I click on the curves with the intersection option chosen, it shows only one intersection point. I can find more intersections points by clicking on the part of the curves located closer to the points (inconvenient), but when changing the parameter to some other values, the points emerge, and when choosing the previous values of the parameter they stay emerged and not all the intersections are shown.

Is there anyway to overcome this problem?

Files: zad1.ggb

Comments (2)


Update: I managed to do what I wanted - to insert manually Intersect(f, g, -100, 100) instead of the graphic menu.

However, I would like to use the point names A1,A2,.. An instead of A,B,C,....


The automatic influencing of the naming of objects is clearly one of the more difficult topics.

You will have to familiarize yourself with list processing (Sequence, Zip) and/or with spreadsheets and/or with Scipts (Execute) quite well.

Different solutions are available: Depending on what you need the points for (as an object) and depending on the purpose of the label.

In the attachment 2 variants:


The points are in a list and cannot be clicked individually. Based on this list, further lists of any complexity can be created using list operations (Sequence). For example: by adding a name to the points as text.


The points are also in a list. But this list is not visible in the graphic. Instead, the values of the points are "fetched" with commands within the spreadsheet and displayed with the cell name in the graphic. The points within the spreadsheet are not in a list and can therefore be clicked and used individually for further construction steps.


You renounce the individual labeling.


The variants 1) and 2) are based on a list. This is simply created by placing the Intersect command in curly brackets {Intersect(f, g, -100, 100)}

I think variant 1 is easier. You basically need the basic knowledge of Sequence() and Text(). You can explore both commands in the manual.

For specific questions I will be at your disposal (please attach the current status of your applet).


Note: in GGB-5 you must press F9 at begin

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