Asymptote is a vector language for 2D and 3D computer graphics. Asymptote code can be included in LaTeX documents or used to generate PostScript, PDF, SVG, WebGL, and PRC files. Interactive 3D PDF files created from Asymptote code require Acrobat Reader version 9 or higher.
Asymptote support was added in FreeCAD version 0.19.
You need the Asymptote compiler to convert *.asy files. To convert to PDF a LaTeX system is also required.
The compiler is a command line tool. To covert to PDF you can use this syntax:
PathToAsyExecutable/asy -f pdf AsymptoteFileName.asy
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