How this calculation works
Inset the rectangle, divide each edge into enough equal intervals to respect the entered maximum gap and count each corner once. Add interior points from a separate evenly redistributed grid.
Perimeter count = 2 × (ceil(active width / edge gap) + ceil(active height / edge gap)); interior = (ceil(active width / field gap) − 1) × (ceil(active height / field gap) − 1)A worked example
A 1,200 × 2,400 mm panel with 50 mm setback leaves 1,100 × 2,300 mm. At 200 mm edge and 400 mm field gaps, 36 perimeter points plus ten interior points give 46 unique positions.
Good to know
A coordinate illustration only, not structural spacing, safe fastener selection, support location or wind-load design. At most 2,000 plotted positions. Edge and interior grids need not align.
Reference: OpenStax: geometric measurement and coordinates (opens in a new tab) ↗
Maximum spacing becomes an actual equal gap
An entered gap is a maximum, not a command to leave one short residual interval at the end. The model rounds the interval count up and redistributes points evenly across each active edge.
Actual horizontal and vertical edge gaps can therefore differ while both remain at or below the same entered maximum. Their values are reported with the final coordinate list.
The lighting lumen grid calculator adds estimate a lumen-method fixture count and complete rectangular schematic grid from entered average lux, utilization and maintenance factors.
Count a shared corner once
Each corner belongs to two edges but represents one physical fastener position. The perimeter formula counts intervals around the closed rectangle rather than adding four endpoint-inclusive lists without deduplication.
Interior points exclude the setback boundary, so they do not duplicate perimeter points. Their grid is computed independently and is not an inferred stud or support pattern.
Coordinates do not establish structural suitability
The plot uses the same unit on both axes and shows unjoined points rather than a misleading travel path. The table provides the exact model coordinates in millimetres.
A valid numerical pattern does not show that material edges, supports or fasteners can carry a load. Enter values from an appropriate design rather than treating the illustrated defaults as recommendations.
Use the result with the next measurement
The lighting lumen grid calculator also draws evenly distributed points, but its fixture count comes from a separate average-lumen model rather than panel-edge fastening rules.
A coordinate illustration only, not structural spacing, safe fastener selection, support location or wind-load design. At most 2,000 plotted positions. Edge and interior grids need not align.
A few questions, answered
Are corners counted twice?
No, each perimeter corner is unique.
Does the interior grid locate supports?
No, support geometry is not modeled.
Does this choose safe spacing?
No, all spacing and setback values are entered assumptions.