Why generate a hole pattern
Bolt patterns, mounting grids, and perforation layouts all come down to the same underlying task: placing evenly spaced holes across rows and columns. Working out each coordinate by hand invites arithmetic mistakes, especially past a handful of holes, and a single wrong offset can mean a scrapped part or a fixture that does not line up.
How the coordinates are calculated
Each hole position is the starting X or Y coordinate plus its row or column index multiplied by the spacing for that axis. The first hole sits at your start X and start Y, and every hole after that steps outward by the spacing value until the full grid of rows and columns is filled in. The result is a complete list of X, Y coordinates ready to drop into a CAM program or a manual point to point drilling cycle.
Practical tips
Double check your start point against the part origin or work coordinate system before cutting, since a grid generated from the wrong corner will still look correct on screen but land in the wrong place on the material. For patterns that need to be centered on a part rather than started from a corner, calculate the total pattern width and height first, then set start X and Y to center that grid within the stock.