Set shape transparency for pdf_out export via skill

Hello.

I am writing a SKILL script to export a PDF of the gerber files with correct parameters. I am trying to set the transparency level of the filled shapes to 0 using axlSetVariable() so that the gerber shapes are black but it doesn't work.

Here is the code :

; get the current shape transparency setting
shapeTransparency = axlGetVariable("pdf_filled_shape_transparency")
println(shapeTransparency)

; set transparency to 0
println(axlSetVariable("pdf_filled_shape_transparency" 0))
println(shapeTransparency)

; print PDFs
sprintf(cmd, "pdf_out BOARD_NAME.brd -o 1 -f ARTWORK_NAME -s -B -a -p -h -c gerberPDF.conf")
axlRunBatchDBProgram("pdfout" cmd ?noUnload t )

; set back transparency to previous value
axlSetVariable("pdf_filled_shape_transparency" shapeTransparency)
println(shapeTransparency)

I can read the current shape transparency setting. However, each time I println it through the program, I always get the same value. It seems like axlSetVariable() doesn't work here. I have tried using axlSetVariableFile() with the same results.

Anyone has an idea what might be wrong here ?

Thank you!