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### How to define range of plot?

Posted: 13 May 2022, 22:01
Hi all!

I'm trying to make a visualization of the intersection of a 3D-fan with the hyperplane \( \{z=1\} \). I have made the following code:

Code: Select all

```application('fan'); \$p = new Polytope<Rational>(POINTS=>[[1,2,0,1],[1,1,1,0],[1,0,2,1],[1,1,0,0],[1,0,1,0],[1,0,0,2]]); \$f = normal_fan<Rational>(\$p); \$H = new Polytope<Rational>(POINTS=>[[1,-1,-1,1],[1,1,-1,1],[1,-1,1,1],[1,1,1,1]]); compose(\$f->VISUAL,\$H->VISUAL); ```
However, the range of the plot of the fan is too small, so it doesn't intersect the hyperplane in the visualization. How do I define the range of the plot of a fan?

### Re: How to define range of plot?

Posted: 15 Jun 2022, 17:33
Hi EFR,

you can change the size of your plotted fan with the Transformation option:

Code: Select all

```application('fan'); \$p = new Polytope<Rational>(POINTS=>[[1,2,0,1],[1,1,1,0],[1,0,2,1],[1,1,0,0],[1,0,1,0],[1,0,0,2]]); \$f = normal_fan<Rational>(\$p); # same Hyperplane as yours but a little bigger and bounded by \$bf \$H = new Polytope<Rational>(EQUATIONS=>[[-1,0,0,1]], INEQUALITIES=>[[1,0,0,0]]); \$bf = cube(3,2,-2)->FACETS; \$factor = 2; \$trafo = diag(new Vector<Float>([\$factor,\$factor,\$factor])); compose(\$f->VISUAL(Transformation=>\$trafo), \$H->VISUAL(BoundingFacets=>\$bf)); ```
I hope this still helps.