No line and no marks in plot to use fillbetween

Question

This seems like it should be simple, but I was unable to find any line style or line width that allows one to have no line in a plot.

I want to draw to plots without a line (0 line width), and then use fillbetween to shade the area between the plots. Probably something obvious that I'm missing, but I couldn't find an equivalent no marks option like 'no line'.

MWE

\documentclass[border=5pt]{standalone}
\usepackage{pgfplots}
\usepgfplotslibrary{fillbetween}
\pgfplotsset{compat=1.15}

\begin{document}
\begin{tikzpicture}
  \begin{axis}[
    xmin=-3, xmax=3,
    samples=100,
    ]   
    \addplot[name path=x3,] {x^3};
    \addplot[name path=x2,] {x^2};
    \addplot[gray, opacity=0.2] fill between[of=x3 and x2];
  \end{axis}
\end{tikzpicture}
\end{document}

Answer 1

Are you looking for draw=none?

\documentclass[border=5pt]{standalone}
\usepackage{pgfplots}
\usepgfplotslibrary{fillbetween}
\pgfplotsset{compat=1.15}

\begin{document}
\begin{tikzpicture}
  \begin{axis}[
    xmin=-3, xmax=3,
    samples=100,
    ]   
    \addplot[name path=x3,draw=none] {x^3};
    \addplot[name path=x2,draw=none] {x^2};
    \addplot[gray, opacity=0.2] fill between[of=x3 and x2];
  \end{axis}
\end{tikzpicture}
\end{document}