The standard explicitly says: Do not use the manufacturer's recommended land pattern unless they provide the IPC-7351C calculation data. Why? Because many component datasheets recommend patterns that are dangerously small for solder paste assembly—they were designed for hand soldering decades ago. The interesting story is that the PDF is quietly telling you that component makers themselves have been giving bad advice for years.
Once you have the official , how do you apply it? Here is a step-by-step workflow for PCB design engineers using Altium, KiCad, Cadence Allegro, or Eagle. ipc-7351c pdf
Most PDFs you find will show you the pad dimensions. The deep text explains : The standard explicitly says: Do not use the
that follow the actual component shape to save space. Zero Orientation Mixed standards between IEC and IPC. The interesting story is that the PDF is
A move toward rounded rectangle pad shapes over traditional oblong shapes to improve solder paste release.