Draw("surf3 same") on top of lego plot

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1

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ROOT Version: 6.36.16
Platform: macosxarm64
Compiler: Apple clang version 21.0.0 (clang-2100.0.123.102)

There is probably an easy way to do this, but I haven’t found it. I would like to do something similar to hist->Draw(“surf3”) but with the histogram plotted as a lego(3) and associated function plotted as the contours on the upper plane. The closest that I can come is


  int maxFill = 200000;
  TH2D *myH = new TH2D("myH", "myH", 100, -3, 3, 100, -3, 3);
  TF2 *myTF2 = new TF2("myTF2", "[0]*exp(-([2]*x*x + [3]*y*y)/[1])", -3, 3, -3, 3);
  myTF2->SetParameters(10.0, 1.0, 1.0, 0.5);
  Double_t a,b;
  for (int i = 0; i < maxFill; i++) {
    myTF2->GetRandom2(a,b);
    myH->Fill(a,b);
  }

  myH->Draw("LEGO2");
  
  myH->Fit("myTF2", "O");

  myH->GetFunction("myTF2")->Draw("surf3 same");

There are two problems with this solution. First, the function is also plotted on the lego plot as a surface

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and second, when rotating the view, the contours disappear if viewed from below

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If I were to generalize this request, it would be to be able to plot one TH2 as a 3d plot (ability to choose lego, lego2, lego3, etc would be even better) and another one as a contour plot (with what ever contour options are available–cont, cont1, cont2, colz, etc) on the plane above the plot. This would allow one other switch the histogram and the function, for example.

Thanks for any pointers you have.

Paul

2

Try drawing first the surf plot, then the lego plot. Also, try the latest ROOT version (6.40.02).
With the above I get what I think you’re asking, but note that to not draw the fit the option is a number zero, not a letter O (not sure if that’s what you have in your code, but copying your text above doesn’t result in a zero for me); also, note that I added SetLineWidth(0) to myTF2, otherwise, the red lines are shown when drawing with surf3.

{
  int maxFill = 200000;
  TH2D *myH = new TH2D("myH", "myH", 100, -3, 3, 100, -3, 3);
  TF2 *myTF2 = new TF2("myTF2", "[0]*exp(-([2]*x*x + [3]*y*y)/[1])", -3, 3, -3, 3);
  myTF2->SetParameters(10.0, 1.0, 1.0, 0.5);
  Double_t a,b;
  for (int i = 0; i < maxFill; i++) {
    myTF2->GetRandom2(a,b);
    myH->Fill(a,b);
  }
  //myH->Draw("LEGO2");
  myH->Fit("myTF2", "0");
  myH->GetFunction("myTF2")->SetLineWidth(0);
  myH->GetFunction("myTF2")->Draw("surf3");
  myH->Draw("LEGO2 same");
}

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