# Externalization with Asymptote

There is a way to externalize pictures with Latex. I've created a folder qwe in the directory where my main document.tex sits and typed:

\documentclass[a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{tikz}
\usetikzlibrary{quotes,angles}
\usetikzlibrary{external}
\tikzexternalize[prefix=qwe/]
\begin{document}
\begin{tikzpicture}
\draw
(3,-1) coordinate (a) node[right] {a}
-- (0,0) coordinate (b) node[left] {b}
-- (2,2) coordinate (c) node[above right] {c}
pic["$\alpha$", draw=red, <->, angle eccentricity=1.2, angle radius=1cm]
{angle=a--b--c};
\end{tikzpicture}
\end{document}


Works like a charm! Although, I create Asymptote pictures.

Is there any analog to externalize TikZ library but for Asymptote? And how to use it?

(I have ~300 pictures in Asymptote and want to save time waiting until they all are being compiled. I bumped into externalzie option when I have the same problem with TikZ)

What I did (do when using asymptote) is to process the figures separately to PDF, and use \pgfimage{} (from the pgf package) to include it in the document. That way, complex images (like some 3D ones, that take quite a while to process) are only recompiled when they change (very rarely). That way, I can look at/tweak the images separately.