Note 002 · S1 Parameters · 29 Oct 2026
Cabinet size, not module size, is what decides where a wall ends
A wall is not cut to the opening. It is assembled from cabinets, and every cabinet is a whole number of modules. Get the module size wrong and the wall finishes short.
Every Fortis cabinet is a multiple of a 250 mm module: 1000 × 500, 1000 × 250, 750 × 250 and 500 × 250 mm, from 9.8 kg down to 3.0 kg. Wall length therefore lands on 250 mm steps, so a 6.4 m opening is built at 6.25 m or 6.50 m.
The cabinet is the unit of construction, the module is the unit of repair
Two grids run through every LED wall and they are not the same grid. The module is the piece a service technician lifts out; the cabinet is the piece a rigger bolts to the structure. Cabinets are built from whole modules, so the cabinet dimensions are all multiples of the module — and the wall, in turn, is a whole number of cabinets.
That chain is why an opening of 6.4 m cannot be filled to the millimetre. Nobody cuts a module. Fortis uses a 250 × 250 mm module, and all four cabinet sizes are multiples of it, so every reachable width is a multiple of 250 mm.
Fortis, in its four cabinet sizes
| Cabinet W × H × D (mm) | Modules per cabinet | Resolution (px) | Weight (kg) | Where it earns its place |
|---|---|---|---|---|
| 1000 × 500 × 33 | 4 × 2 | 384 × 192 | 9.8 | Bulk of the wall, fewest joints |
| 1000 × 250 × 33 | 4 × 1 | 384 × 96 | 5.0 | Closing a height that is 250 mm off |
| 750 × 250 × 33 | 3 × 1 | 288 × 96 | 4.0 | Columns that must clear a door or a column |
| 500 × 250 × 33 | 2 × 1 | 192 × 96 | 3.0 | Corners and returns, one hand to carry |
All four sizes exist in Lite P2.6, Standard P1.95 and Ultra P1.56; the 250 mm module is common to all three.
What 6.4 m actually becomes
Run the arithmetic on the grid instead of the drawing. Five 1000 mm cabinets plus one 750 mm plus one 500 mm gives 6.25 m. Six 1000 mm plus one 500 mm gives 6.50 m. There is nothing in between, because 250 mm is the smallest step and 6400 mm is not a multiple of it.
| Combination | Width (m) | Gap to 6.4 m (mm) |
|---|---|---|
| 5 × 1000 + 750 + 500 | 6.25 | 150 short |
| 6 × 1000 + 500 | 6.50 | 100 over |
| 6 × 1000 | 6.00 | 400 short |
Target opening is 6.4 m; the grid steps in 250 mm, so the nearest buildable widths are 6.25 m and 6.50 m.
The rule, and the order to apply it in
If the opening is fixed by the building, then pick the cabinet mix that lands just under it and take the remainder as a reveal or a frame. If the wall size is still open, then set it to a multiple of 250 mm and give the architect that number, not a round one.
- Fix the nearest standing distance, which sets the pitch.
- Round the pitch choice to a real series, then read its module size off the sheet.
- Set wall width and height to multiples of that module.
- Choose the cabinet mix last — it changes the joint layout and the weight per lift, not the resolution.
- Hand the architect the real width, and put the remainder in the joinery detail.
Where this stops being true
1. The wall is a video wall of separate panels, not a continuous surface. Then every panel is framed on all four sides, the 250 mm grid no longer governs, and the gaps between panels are a design decision rather than a leftover.
2. The wall is curved or wraps a corner. A 250 mm module cannot follow a tight radius without a faceted cabinet or a flexible module. Below roughly a 3 m radius the arithmetic above gives an answer that will not physically close.
3. The remainder has to be lit, not framed. If the client will not accept a 150 mm reveal, the answer is not a finer cabinet — it is a custom cabinet, which moves the order out of the standard grid and into a tooling lead time.
One thing we got wrong ourselves
We used to quote wall size from the module rather than the cabinet, on the argument that modules are what you add or remove. That is true for repair and false for construction: a module row cannot be added on its own, because the cabinet that carries it has a fixed height. We now size walls from the cabinet set and use the module only to explain service.
- Datasheet — Fortis series sheets, Lite P2.6 / Standard P1.95 / Ultra P1.56: module size 250 × 250 mm, four cabinet sizes 1000 × 500, 1000 × 250, 750 × 250, 500 × 250 mm, weights 9.8 / 5.0 / 4.0 / 3.0 kg, cabinet resolutions 384 × 192 down to 192 × 96.
- Practice — The convention of building fixed indoor walls on whole cabinets and reserving the module grid for service access, as used on our own installations. It is a construction practice, not a published standard.
Questions we get on this
Not from standard Fortis cabinets. The module is 250 mm and every cabinet is a multiple of it, so widths step in 250 mm. 6.40 m falls between 6.25 m and 6.50 m; only a custom cabinet closes the difference.
No. Resolution is set by pitch and area, not by how the area is divided. A 500 × 250 mm cabinet at P2.6 carries 192 × 96 px, the same pixel density as the 1000 × 500 mm cabinet beside it.
Send the opening and the nearest sightline, not a round number.
We will return the cabinet mix that lands under your opening, the remainder in millimetres, and the weight of the heaviest single lift — in writing, with the exception stated.