How to draw a cube with TikZ where all faces have a distinct color?

Question

For each face, to show a distinct color I guess we have to use opacity, but at this point, this problem seemed out of my hand. Could anyone help me out?

My attempt

\documentclass{article}
\usepackage{tikz}

\definecolor{cof}{RGB}{219,144,71}
\definecolor{pur}{RGB}{186,146,162}
\definecolor{greeo}{RGB}{91,173,69}
\definecolor{greet}{RGB}{52,111,72}

\begin{document}

\begin{tikzpicture}[thick,scale=3]
    \coordinate (A1) at (0, 0);
    \coordinate (A2) at (0, 1);
    \coordinate (A3) at (1, 1);
    \coordinate (A4) at (1, 0);
    \coordinate (B1) at (0.3, 0.3);
    \coordinate (B2) at (0.3, 1.3);
    \coordinate (B3) at (1.3, 1.3);
    \coordinate (B4) at (1.3, 0.3);

    \draw[very thick] (A1) -- (A2);
    \draw[very thick] (A2) -- (A3);
    \draw[very thick] (A3) -- (A4);
    \draw[very thick] (A4) -- (A1);

    \draw[dashed] (A1) -- (B1);
    \draw[dashed] (B1) -- (B2);
    \draw[very thick] (A2) -- (B2);
    \draw[very thick] (B2) -- (B3);
    \draw[very thick] (A3) -- (B3);
    \draw[very thick] (A4) -- (B4);
    \draw[very thick] (B4) -- (B3);
    \draw[dashed] (B1) -- (B4);

    \draw[fill=yellow,opacity=0.6] (A1) -- (B1) -- (B4) -- (A4);
    \draw[fill=black!20,opacity=0.5] (A1) -- (A2) -- (A3) -- (A4);
    \draw[fill=red,opacity=0.6] (A1) -- (A2) -- (B2) -- (B1);
    \draw[fill=black,opacity=0.6] (B1) -- (B2) -- (B3) -- (B4);
    \draw[fill=blue,opacity=0.6] (A3) -- (B3) -- (B4) -- (A4);
    \draw[fill=green,opacity=0.6] (A2) -- (B2) -- (B3) -- (A3);

\end{tikzpicture}

\end{document}

Answer 1

To start consider how you would draw a cube on paper, and draw those lines with TikZ. Start with one face and then add the sides, depending on what view you want.

Here is one way to do it:

\documentclass{article}
\usepackage{tikz}
\usepackage{xcolor}
\begin{document}
\newcommand{\Depth}{2}
\newcommand{\Height}{2}
\newcommand{\Width}{2}
\begin{tikzpicture}
\coordinate (O) at (0,0,0);
\coordinate (A) at (0,\Width,0);
\coordinate (B) at (0,\Width,\Height);
\coordinate (C) at (0,0,\Height);
\coordinate (D) at (\Depth,0,0);
\coordinate (E) at (\Depth,\Width,0);
\coordinate (F) at (\Depth,\Width,\Height);
\coordinate (G) at (\Depth,0,\Height);

\draw[blue,fill=yellow!80] (O) -- (C) -- (G) -- (D) -- cycle;% Bottom Face
\draw[blue,fill=blue!30] (O) -- (A) -- (E) -- (D) -- cycle;% Back Face
\draw[blue,fill=red!10] (O) -- (A) -- (B) -- (C) -- cycle;% Left Face
\draw[blue,fill=red!20,opacity=0.8] (D) -- (E) -- (F) -- (G) -- cycle;% Right Face
\draw[blue,fill=red!20,opacity=0.6] (C) -- (B) -- (F) -- (G) -- cycle;% Front Face
\draw[blue,fill=red!20,opacity=0.8] (A) -- (B) -- (F) -- (E) -- cycle;% Top Face

%% Following is for debugging purposes so you can see where the points are
%% These are last so that they show up on top
%\foreach \xy in {O, A, B, C, D, E, F, G}{
%    \node at (\xy) {\xy};
%}
\end{tikzpicture}
\end{document}

Adjust the opacity and color of the sides as you wish.

I also left some debugging code in there so you can see where the coordinates are.

Answer 2

I think the tikz-3dplot package needs more promotion. It makes life much easier.

\documentclass{minimal}
\usepackage{tikz,tikz-3dplot}

\begin{document}
  \tdplotsetmaincoords{70}{115}

  \begin{tikzpicture}[scale=4,tdplot_main_coords]
    \coordinate (O) at (0,0,0);
    \tdplotsetcoord{P}{1.414213}{54.68636}{45}

    \draw[fill=gray!50,fill opacity=0.5] (O) -- (Py) -- (Pyz) -- (Pz) -- cycle;
    \draw[fill=blue,fill opacity=0.5] (O) -- (Px) -- (Pxy) -- (Py) -- cycle;
    \draw[fill=yellow,fill opacity=0.5] (O) -- (Px) -- (Pxz) -- (Pz) -- cycle;
    \draw[fill=green,fill opacity=0.5] (Pz) -- (Pyz) -- (P) -- (Pxz) -- cycle;
    \draw[fill=red,fill opacity=0.5] (Px) -- (Pxy) -- (P) -- (Pxz) -- cycle;
    \draw[fill=magenta,fill opacity=0.5] (Py) -- (Pxy) -- (P) -- (Pyz) -- cycle;
  \end{tikzpicture}
\end{document}

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