knitr does not build vignette

Question

I am writing a package vignette with Rmarkdown. I tried to follow all the tuto from Hadley, Yihui, Rstudio cheat sheet... but I still don't manage to embed the vignette correctly.

For now I have a .Rmd file which compiles fine by pressing Rstudio button "knit". However:

• devtools::build_vignettes() returns NULL
• building a source package and running R CMD INSTALL does nothing to the /vignettes folder
• I have checked the box use roxygen for vignette in Rstudio parameters
• when I compile with Rstudio, it saves the .pdf output in a wired temp directory:

Output created: /private/var/folders/53/l9bfpvgj4y7brgnjwym34kph0000gn/T/RtmpydyKqk/preview-ffc141c28b47.dir/mistral-vignette.pdf

Since my vignette is pretty long to build I would be happy to just include the .pdf output

---

The YAML input:

---
title: "Using mistral for reliability analysis"
author: "Clément Walter"
date: '`r Sys.Date()`'
output: rmarkdown::pdf_document
vignette: >
  %\VignetteIndexEntry{Using mistral for reliability analysis}
  %\VignetteEngine{rmarkdown::render}
  %\VignetteEncoding{UTF-8}
  \usepackage[utf8]{inputenc}
  \DeclareUnicodeCharacter{00A0}{ }
---

In the DESCRIPTION file, I have added:

VignetteBuilder: knitr
Suggests: knitr, rmarkdown