3

Consider the following 3D surface graphs created using the tikz-3dplot package:

\documentclass{article}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usepackage{caption}
\usepackage{subcaption}
\usepackage[outline]{contour}
\contourlength{0.05em}

\begin{document}

\begin{figure}[ht]
 \hfill
 \begin{subfigure}{.333333\linewidth}
  \centering
  \tdplotsetmaincoords{70}{-22.5}
  \begin{tikzpicture}[scale=2.8,tdplot_main_coords]
  \foreach \index in {1,...,9}
   {\draw[domain=0:1,smooth]
      plot
        (\x,\index/10,
         {\x*\index/10*(\x+\index/10-\x*\index/10)});
    \draw[domain=0:1,smooth]
      plot
        (\index/10,\x,
         {\x*\index/10*(\x+\index/10-\x*\index/10)});}
  \draw
    (0,1,0) -- (1,1,1) -- (1,0,0);
  \draw[dashed]
    (0,0,1) node[left] {$1$} --
    (1,0,1) -- (1,1,1) -- (0,1,1) -- cycle;
  \draw[dashed]
    (1,0,1) -- (1,0,0) node[below] {$1\mathstrut$};
  \draw[dashed]
    (0,1,1) -- (0,1,0) node[below] {$1\mathstrut$};
  \draw[thick,latex-latex]
    (0,1.2,0) node[below] {$v\mathstrut$} --
    (0,0,0)   node[below] {$O\mathstrut$} --
    (1.2,0,0) node[below] {$u\mathstrut$};
  \draw[thick,-latex]
    (0,0,0) --
    (0,0,1.2) node[above] {\contour{white}{$C_{-1}(u,v)$}};
  \end{tikzpicture}
  \caption{$C_{-1}(u,v)$.}
 \end{subfigure}%
 \hfill
 \begin{subfigure}{.333333\linewidth}
  \centering
  \tdplotsetmaincoords{70}{-22.5}
  \begin{tikzpicture}[scale=2.8,tdplot_main_coords]
  \foreach \index in {1,...,9}
   {\draw[domain=0:1,smooth]
      plot
        (\x,\index/10,
         {\x*\index/10*(2-\x-\index/10+\x*\index/10)});
    \draw[domain=0:1,smooth]
      plot
        (\index/10,\x,
         {\x*\index/10*(2-\x-\index/10+\x*\index/10)});}
  \draw
    (0,1,0) -- (1,1,1) -- (1,0,0);
  \draw[dashed]
    (0,0,1) node[left] {$1$} --
    (1,0,1) -- (1,1,1) -- (0,1,1) -- cycle;
  \draw[dashed]
    (1,0,1) -- (1,0,0) node[below] {$1\mathstrut$};
  \draw[dashed]
    (0,1,1) -- (0,1,0) node[below] {$1\mathstrut$};
  \draw[thick,latex-latex]
    (0,1.2,0) node[below] {$v\mathstrut$} --
    (0,0,0)   node[below] {$O\mathstrut$} --
    (1.2,0,0) node[below] {$u\mathstrut$};
  \draw[thick,-latex]
    (0,0,0) --
    (0,0,1.2) node[above] {\contour{white}{$C_1(u,v)$}};
  \end{tikzpicture}
  \caption{$C_1(u,v)$.}
 \end{subfigure}%
 \hfill\strut
\caption{Plots of the Farlie--Gumbel--Morgenstern copulae~$C_{-1}$ and~$C_1$.}
\end{figure}

\end{document}

copulae

Is there a method to create the above 3D graphs, with perspective? More precisely, can anyone create a perspective drawing with two vanishing points on the horizon, which automates all necessary computations?

This answer by @JanHlavacek attempted to draw a cube with perspective, but I doubt the application to my situation.

Ruixi Zhang
  • 9,553
  • 1
    Yes, but the only example I am aware of is this one. Terribly undervoted IMHO. Of course, asymptote does this, too. –  Sep 04 '18 at 14:57
  • 1
    I need to correct myself. Here seems to be another package that deals with perspectives. Just found it now, and have no idea what is status is, nor have I tried it out. It is used in this answer. –  Sep 04 '18 at 23:25

1 Answers1

6

All the conceptual issues have been solved by Max in this fantastic answer, which I just copied in the updated answer. In my original answer, I used a more clumsy syntax, but this is no longer necessary since Max has fixed it.

UPDATED ANSWER: Max' coordinate parser works, according to what I find, just great. The only exception is when the coordinates contain a newline, i.e. stretch over more than one line. FIXED BY MAX It is just Max' stellar transformations + your code + tpp cs: added to all coordinates.

\documentclass{article}
% Max preamble
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usepgfmodule{nonlineartransformations}
\usepackage{mathtools}
% Ruixi packages
\usepackage{caption}
\usepackage{subcaption}
\usepackage[outline]{contour}
\contourlength{0.05em}
% Max magic
\makeatletter 
% the first part is not in use here
\def\tikz@scan@transform@one@point#1{%
  \tikz@scan@one@point\pgf@process#1%
  \pgf@pos@transform{\pgf@x}{\pgf@y}}
\tikzset{%
  grid source opposite corners/.code args={#1and#2}{%
   \pgfextract@process\tikz@transform@source@southwest{%
     \tikz@scan@transform@one@point{#1}}%
   \pgfextract@process\tikz@transform@source@northeast{%
     \tikz@scan@transform@one@point{#2}}%
  },
  grid target corners/.code args={#1--#2--#3--#4}{%
   \pgfextract@process\tikz@transform@target@southwest{%
     \tikz@scan@transform@one@point{#1}}%
   \pgfextract@process\tikz@transform@target@southeast{%
     \tikz@scan@transform@one@point{#2}}%
   \pgfextract@process\tikz@transform@target@northeast{%
     \tikz@scan@transform@one@point{#3}}%
   \pgfextract@process\tikz@transform@target@northwest{%
     \tikz@scan@transform@one@point{#4}}%
  }
}

\def\tikzgridtransform{%
  \pgfextract@process\tikz@current@point{}%
  \pgf@process{%
    \pgfpointdiff{\tikz@transform@source@southwest}%
      {\tikz@transform@source@northeast}%
  }%
  \pgf@xc=\pgf@x\pgf@yc=\pgf@y%
  \pgf@process{%
    \pgfpointdiff{\tikz@transform@source@southwest}{\tikz@current@point}%
  }%
  \pgfmathparse{\pgf@x/\pgf@xc}\let\tikz@tx=\pgfmathresult%
  \pgfmathparse{\pgf@y/\pgf@yc}\let\tikz@ty=\pgfmathresult%
  %
  \pgfpointlineattime{\tikz@ty}{%
    \pgfpointlineattime{\tikz@tx}{\tikz@transform@target@southwest}%
      {\tikz@transform@target@southeast}}{%
    \pgfpointlineattime{\tikz@tx}{\tikz@transform@target@northwest}%
      {\tikz@transform@target@northeast}}%
}

% Initialize H matrix for perspective view
\pgfmathsetmacro\H@tpp@aa{1}\pgfmathsetmacro\H@tpp@ab{0}\pgfmathsetmacro\H@tpp@ac{0}%\pgfmathsetmacro\H@tpp@ad{0}
\pgfmathsetmacro\H@tpp@ba{0}\pgfmathsetmacro\H@tpp@bb{1}\pgfmathsetmacro\H@tpp@bc{0}%\pgfmathsetmacro\H@tpp@bd{0}
\pgfmathsetmacro\H@tpp@ca{0}\pgfmathsetmacro\H@tpp@cb{0}\pgfmathsetmacro\H@tpp@cc{1}%\pgfmathsetmacro\H@tpp@cd{0}
\pgfmathsetmacro\H@tpp@da{0}\pgfmathsetmacro\H@tpp@db{0}\pgfmathsetmacro\H@tpp@dc{0}%\pgfmathsetmacro\H@tpp@dd{1}

%Initialize H matrix for main rotation
\pgfmathsetmacro\H@rot@aa{1}\pgfmathsetmacro\H@rot@ab{0}\pgfmathsetmacro\H@rot@ac{0}%\pgfmathsetmacro\H@rot@ad{0}
\pgfmathsetmacro\H@rot@ba{0}\pgfmathsetmacro\H@rot@bb{1}\pgfmathsetmacro\H@rot@bc{0}%\pgfmathsetmacro\H@rot@bd{0}
\pgfmathsetmacro\H@rot@ca{0}\pgfmathsetmacro\H@rot@cb{0}\pgfmathsetmacro\H@rot@cc{1}%\pgfmathsetmacro\H@rot@cd{0}
%\pgfmathsetmacro\H@rot@da{0}\pgfmathsetmacro\H@rot@db{0}\pgfmathsetmacro\H@rot@dc{0}\pgfmathsetmacro\H@rot@dd{1}

\pgfkeys{
    /three point perspective/.cd,
        p/.code args={(#1,#2,#3)}{
            \pgfmathparse{int(round(#1))}
            \ifnum\pgfmathresult=0\else
                \pgfmathsetmacro\H@tpp@ba{#2/#1}
                \pgfmathsetmacro\H@tpp@ca{#3/#1}
                \pgfmathsetmacro\H@tpp@da{ 1/#1}
                \coordinate (vp-p) at (#1,#2,#3);
            \fi
        },
        q/.code args={(#1,#2,#3)}{
            \pgfmathparse{int(round(#2))}
            \ifnum\pgfmathresult=0\else
                \pgfmathsetmacro\H@tpp@ab{#1/#2}
                \pgfmathsetmacro\H@tpp@cb{#3/#2}
                \pgfmathsetmacro\H@tpp@db{ 1/#2}
                \coordinate (vp-q) at (#1,#2,#3);
            \fi
        },
        r/.code args={(#1,#2,#3)}{
            \pgfmathparse{int(round(#3))}
            \ifnum\pgfmathresult=0\else
                \pgfmathsetmacro\H@tpp@ac{#1/#3}
                \pgfmathsetmacro\H@tpp@bc{#2/#3}
                \pgfmathsetmacro\H@tpp@dc{ 1/#3}
                \coordinate (vp-r) at (#1,#2,#3);
            \fi
        },
        coordinate/.code args={#1,#2,#3}{
           \pgfmathsetmacro\tpp@x{#1} %<- Max' fix
            \pgfmathsetmacro\tpp@y{#2}
            \pgfmathsetmacro\tpp@z{#3}
        },
}

\tikzset{
    view/.code 2 args={
        \pgfmathsetmacro\rot@main@theta{#1}
        \pgfmathsetmacro\rot@main@phi{#2}
        % Row 1
        \pgfmathsetmacro\H@rot@aa{cos(\rot@main@phi)}
        \pgfmathsetmacro\H@rot@ab{sin(\rot@main@phi)}
        \pgfmathsetmacro\H@rot@ac{0}
        % Row 2
        \pgfmathsetmacro\H@rot@ba{-cos(\rot@main@theta)*sin(\rot@main@phi)}
        \pgfmathsetmacro\H@rot@bb{cos(\rot@main@phi)*cos(\rot@main@theta)}
        \pgfmathsetmacro\H@rot@bc{sin(\rot@main@theta)}
        % Row 3
        \pgfmathsetmacro\H@m@ca{sin(\rot@main@phi)*sin(\rot@main@theta)}
        \pgfmathsetmacro\H@m@cb{-cos(\rot@main@phi)*sin(\rot@main@theta)}
        \pgfmathsetmacro\H@m@cc{cos(\rot@main@theta)}
        % Set vector values
        \pgfmathsetmacro\vec@x@x{\H@rot@aa}
        \pgfmathsetmacro\vec@y@x{\H@rot@ab}
        \pgfmathsetmacro\vec@z@x{\H@rot@ac}
        \pgfmathsetmacro\vec@x@y{\H@rot@ba}
        \pgfmathsetmacro\vec@y@y{\H@rot@bb}
        \pgfmathsetmacro\vec@z@y{\H@rot@bc}
        % Set pgf vectors
        \pgfsetxvec{\pgfpoint{\vec@x@x cm}{\vec@x@y cm}}
        \pgfsetyvec{\pgfpoint{\vec@y@x cm}{\vec@y@y cm}}
        \pgfsetzvec{\pgfpoint{\vec@z@x cm}{\vec@z@y cm}}
    },
}

\tikzset{
    perspective/.code={\pgfkeys{/three point perspective/.cd,#1}},
    perspective/.default={p={(15,0,0)},q={(0,15,0)},r={(0,0,50)}},
}

\tikzdeclarecoordinatesystem{three point perspective}{
    \pgfkeys{/three point perspective/.cd,coordinate={#1}}
    \pgfmathsetmacro\temp@p@w{\H@tpp@da*\tpp@x + \H@tpp@db*\tpp@y + \H@tpp@dc*\tpp@z + 1}
    \pgfmathsetmacro\temp@p@x{(\H@tpp@aa*\tpp@x + \H@tpp@ab*\tpp@y + \H@tpp@ac*\tpp@z)/\temp@p@w}
    \pgfmathsetmacro\temp@p@y{(\H@tpp@ba*\tpp@x + \H@tpp@bb*\tpp@y + \H@tpp@bc*\tpp@z)/\temp@p@w}
    \pgfmathsetmacro\temp@p@z{(\H@tpp@ca*\tpp@x + \H@tpp@cb*\tpp@y + \H@tpp@cc*\tpp@z)/\temp@p@w}
    \pgfpointxyz{\temp@p@x}{\temp@p@y}{\temp@p@z}
}
\tikzaliascoordinatesystem{tpp}{three point perspective}

\makeatother


\begin{document}
\begin{figure}[ht]
 \hfill
 \begin{subfigure}{.333333\linewidth}
  \centering
  \tdplotsetmaincoords{70}{-22.5}
  \begin{tikzpicture}[scale=pi,%tdplot_main_coords
  view={\tdplotmaintheta}{\tdplotmainphi},
            perspective={
                p = {(4,0,1.5)},
                q = {(0,4,1.5)},
            }
  ]
  \foreach \index in {1,...,9}
   {\draw[domain=0:1,smooth]
      plot
        (tpp cs:\x,\index/10,{\x*\index/10*(\x+\index/10-\x*\index/10)});
    \draw[domain=0:1,smooth]
      plot
        (tpp cs:\index/10,\x,{\x*\index/10*(\x+\index/10-\x*\index/10)});}
  \draw
    (tpp cs:0,1,0) -- (tpp cs:1,1,1) -- (tpp cs:1,0,0);
  \draw[dashed]
    (tpp cs:0,0,1) node[left] {$1$} --
    (tpp cs:1,0,1) -- (tpp cs:1,1,1) -- (tpp cs:0,1,1) -- cycle;
  \draw[dashed]
    (tpp cs:1,0,1) -- (tpp cs:1,0,0) node[below] {$1\mathstrut$};
  \draw[dashed]
    (tpp cs:0,1,1) -- (tpp cs:0,1,0) node[below] {$1\mathstrut$};
  \draw[thick,latex-latex]
    (tpp cs:0,1.2,0) node[below] {$v\mathstrut$} --
    (tpp cs:0,0,0)   node[below] {$O\mathstrut$} --
    (tpp cs:1.2,0,0) node[below] {$u\mathstrut$};
  \draw[thick,-latex]
    (tpp cs:0,0,0) --
    (tpp cs:0,0,1.2) node[above] {\contour{white}{$C_{-1}(u,v)$}};
  \end{tikzpicture}
  \caption{$C_{-1}(u,v)$.}
 \end{subfigure}%
 \hfill
 \begin{subfigure}{.333333\linewidth}
  \centering
  \tdplotsetmaincoords{70}{-22.5}
  \begin{tikzpicture}[scale=pi,%tdplot_main_coords]
  view={\tdplotmaintheta}{\tdplotmainphi},
            perspective={
                p = {(4,0,1.5)},
                q = {(0,4,1.5)},
            }
  ]
  \foreach \index in {1,...,9}
   {\draw[domain=0:1,smooth]
      plot
        (tpp cs:\x,\index/10,{\x*\index/10*(2-\x-\index/10+\x*\index/10)});
    \draw[domain=0:1,smooth]
      plot
        (tpp cs:\index/10,\x,{\x*\index/10*(2-\x-\index/10+\x*\index/10)});}
  \draw
    (tpp cs:0,1,0) -- (tpp cs:1,1,1) -- (tpp cs:1,0,0);
  \draw[dashed]
    (tpp cs:0,0,1) node[left] {$1$} --
    (tpp cs:1,0,1) -- (tpp cs:1,1,1) -- (tpp cs:0,1,1) -- cycle;
  \draw[dashed]
    (tpp cs:1,0,1) -- (tpp cs:1,0,0) node[below] {$1\mathstrut$};
  \draw[dashed]
    (tpp cs:0,1,1) -- (tpp cs:0,1,0) node[below] {$1\mathstrut$};
  \draw[thick,latex-latex]
    (tpp cs:0,1.2,0) node[below] {$v\mathstrut$} --
    (tpp cs:0,0,0)   node[below] {$O\mathstrut$} --
    (tpp cs:1.2,0,0) node[below] {$u\mathstrut$};
  \draw[thick,-latex]
    (tpp cs:0,0,0) --
    (tpp cs:0,0,1.2) node[above] {\contour{white}{$C_1(u,v)$}};
  \end{tikzpicture}
  \caption{$C_1(u,v)$.}
 \end{subfigure}%
 \hfill\strut
\caption{Plots of the Farlie--Gumbel--Morgenstern copulae~$C_{-1}$ and~$C_1$.}
\end{figure}
\end{document}

The perspective is defined in 

perspective={
                p = {(4,0,1.5)},
                q = {(0,4,1.5)},
            }

which you may adjust to your needs.

enter image description here

  • 1
    Oh! I so wish @Max turned the code into a package. – Ruixi Zhang Sep 05 '18 at 14:27
  • @RuixiZhang Me too. He could then add this code as well... –  Sep 05 '18 at 14:33
  • There is only one nitpick: There is another vanishing point in the z-direction (invisible to the human eyes, but still…). I left a comment to @Max wondering if it is possible to suppress that. – Ruixi Zhang Sep 05 '18 at 14:43
  • 2
    @RuixiZhang In this answer by marmot, the vanishing point in z-direction is already turned off. The default value of (0,0,50) only gets activated when you call perspective without argument. If you specify only one or two vanishing points in the argument of perspective, the remaining points simply get turned off. I figured that would be the most intuitive option – Max Sep 05 '18 at 17:39
  • 2
    @RuixiZhang And about turning it into a package, I was thinking about that but it seems to me that a Tikz library would be more appropriate (still have to figure out how to implement that). In a few weeks I will have some more time to work on this probably. – Max Sep 06 '18 at 06:25
  • @Max Yes, a library will be more appropriate. It would be great if you could also add your nice yaw, pitch and roll routines. Unfortunately, tikz-3dplot is a package, not a library. If there is any way I could support you in that task (like playing the guinea pig) I'll be happy to do so. –  Sep 06 '18 at 11:26
  • @Max I think it is because this thing does not transform shapes. But I do not want to pressure you, rather I understand that one might be very hesitant to do that. Apart from all the work you need to do, there will be the problem of maintaining the thing and to deal with incompatibilities and so on. –  Sep 07 '18 at 17:16
  • @Max But this does not even transform the node shapes, please compare the green nodes. (At least your pitch, yaw and roll keys do transform them, don't they?) –  Sep 07 '18 at 17:30
  • @Max I should have been clearer, sorry. The keys do not install a coordinate system, but provide you with one, which you then can use with the 3d library to transform shapes. I was unable to achieve the same with the rotate around x key, but it is quite possible that I did something wrong. Having said this, I do believe that it would be really cool if we had an extension on the 3d library that has all the coordinate transformations built in (and the xy plane fixed such that we do not have to pollute our preambles with the fix). –  Sep 07 '18 at 17:41
  • 1
    @Max Yes, this package is a start, but there is certainly some room for improvement. What I wanted to say is that a simple collection of the nice things you have created in a single package would be a great thing to have. –  Sep 07 '18 at 17:59