Plotting 2D Histogram as a Plane Under a 3D Histogram

[couet]

That’s not really easy to do. What I can propose is something like that:

{
  TH2F *h1 = new TH2F("h1","",40,0,10,40,0,10);
  TH2F *h2 = new TH2F("h2","",40,0,10,40,0,10);

  for(int i =0; i<1000; i++) {
     h1->Fill(gRandom->Gaus(6,1),gRandom->Gaus(6,1));
     h2->Fill(gRandom->Gaus(4,.5),gRandom->Gaus(4,.5));
  }

  h2->SetLineColorAlpha(22,0.);
  gStyle->SetPalette(kBird,0,0.7);
  h1->Draw("surf");
  h2->Draw("surf3 same");
}