You can insert a PDF file as a reference model to your Tekla Structures model. During import, Tekla Structures converts the PDF into the DXF format.
Insert a PDF file to a model
Limitations
Only vector graphics are converted, not raster graphics.
Warning:
WARNING: The PDF document could be subject to minor scaling adjustments during the print process to make it fit a standard page size. That means that it may not be 100% accurate in all directions once scaled to full size.