SMD parts come mounted on a tape, and if you buy many of them, the tape comes on a reel. There are some standards on this. The holes are 1.5mm in diameter and are 4mm apart. There is a hole 2mm from a part center. The tape width is a multiple of 4mm, as is the part pitch, except for 0402 and smaller parts, where the part pitch is 2mm. The part center distance from the holes is width / 2 – 0.5mm. The parts are placed on a tape so, that there is a hole 2mm from a part center. This is our reference hole:
It is up to you to decide which way to put the tape strips on the table. The orientation is the direction where part count increases. The orientations are:
