Grille generator

Generate the coordinates for a mechanical grille.
No. of HolesOpen Area [units^2]Open Area [%]


  • Define an outer diameter and hole size
  • Define swirl
  • Output list of hole coordinates
  • Save-as on page to use offline.

Pattern seed

The pattern generated by this algorithm is fixed. That is, the pattern is scaled and truncated to fit a desired aspect ratio of hole diameter to overall diameter. The distanced between rings and the arc segment between holes on the same ring is approximately because partial holes are not allowed. The pattern is repeated until the next ring would exceed . The infinite unit pattern is thus independent of and .

The algorithm also allows for specification of the initial hole angle and the subsequent phase shift per ring. The main purpose of these are to tweak the pattern to obscure obvious linear radial patterns if desired. The plot on the next page helps illustrate this.