# Unions, Differences, etc.

SharkD shared this idea 6 months ago
Completed

I think it would be great if GeoGebra could create unions, intersections and differences of various shapes, such as curves, polygons, etc.

Thanks.

1

Every GeoGebra object has an algebraic representation, so I think that a general command is not applicable, because of the possible reciprocal positions of an object with respect to another. You can group objects in lists, if you need union.

About intersection and difference, in some selected cases there already are commands:

https://wiki.geogebra.org/e... (see 3D options,too)

I think that - if you don't know it - you might like IntersectPath ;)

1

Are there examples online? The wiki is very terse/minimalistic.

1

: ) it needs to be like this - KISS - We can't add an example for every single user need...

I guess that you should search in our materials platform, there are millions of resources there

1

Okay, it looks like some of the commands you listed work very well for polygons. But I wish they worked for other curves (especially arcs and sectors) as well. Also, most of these commands only generate points. I can intersect two ellipses, for instance. But only the points are plotted, not the region formed by the intersection/difference. This was kind of the point of my original idea post.

1

Inequalities:

Only for coloring combinations (∧ and ∨) of conics, lines (equations) and functions (and using in combination with ClosestPointRegion(), PointIn(), IsInRegion(), {Vertex()} but not Area, Border, Locus...)

(maybe better than nothing)

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Sample tested with GGB 5.0.541 and GGB 6.0.535