Running examples in ‘rgl-Ex.R’ failed
The error most likely occurred in:

> ### Name: plotmath3d
> ### Title: Draw text using base graphics math plotting
> ### Aliases: plotmath3d
> 
> ### ** Examples
> 
> open3d()
null 
  68 
> plotmath3d(1:3, 1:3, 1:3, expression(x[1] == 1, x[2] == 2, x[3] == 3))
Warning in graphics::mtext(sprintf("help(\"%s\")", nameEx()), side = 4,  :
  no font could be found for family "Arial"
Warning in graphics::mtext(sprintf("help(\"%s\")", nameEx()), side = 4,  :
  no font could be found for family "Arial"
Warning in graphics::mtext(sprintf("help(\"%s\")", nameEx()), side = 4,  :
  no font could be found for family "Arial"
Warning in strwidth(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strwidth(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strwidth(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strwidth(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strwidth(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strwidth(thistext, cex = initCex, ...) :
  font "Symbol" could not be found for family ""
Warning in strwidth(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strwidth("m", cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strheight(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strheight(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strheight(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strheight(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Warning in strheight(thistext, cex = initCex, ...) :
  font "Symbol" could not be found for family ""
Warning in strheight(thistext, cex = initCex, ...) :
  no font could be found for family "Arial"
Error in png(f, bg = "transparent", width = size, height = size) : 
  invalid quartz() device size
Calls: plotmath3d -> png
Execution halted