Identify the problem the existing floor engine does not solve
A shipment combines eight Euro pallets measuring 1200 × 800 mm and eight industrial pallets measuring 1200 × 1000 mm. The team needs one container proposal for all sixteen loads. The site’s engine accepts one identical rectangle size per run; it does not pack those two types together in a single search. Mixed orientation means the same rectangle can turn ninety degrees, not that different sizes are supported. Make this limitation explicit before using individual tool results in a combined shipment decision.
A practical starting proposal is to divide the floor into nonoverlapping zones and allocate a known quantity to each. That creates a transparent hand-checkable arrangement and allows the identical-size tool to examine each zone separately. It does not necessarily maximize the combined count, because a true mixed-size optimizer could interleave groups more efficiently. The purpose of zoning is to establish a reproducible feasible candidate for the stated shipment, not to claim the best possible mixed-cargo packing.
Construct two zones for the actual quantities
Use the historical forty-foot dry floor of 12032 × 2352 mm as an example. Zone A runs 4800 mm along the length and uses the full modeled width. Four 1200 mm rows with two 800 mm widths each hold eight Euro pallets. Zone B also runs 4800 mm along the length; four 1200 mm rows with two 1000 mm widths hold eight industrial pallets. The two zone lengths sum to 9600 mm, leaving 2432 mm before spacing, perimeter clearance or other exclusions.
Set coordinates so Zone A occupies length positions from 0 to 4800 mm and Zone B from 4800 to 9600 mm. At zero added gap, those regions meet at a boundary but do not overlap. Within Zone A, two Euro widths use 1600 mm; within Zone B, two industrial widths use 2000 mm. Both are below 2352 mm. This explicitly constructs sixteen placements for the two known groups, unlike adding the maximum quantities returned when each group is run separately in the whole container.
| Zone | Pallet group | Uniform arrangement | Occupied rectangle |
|---|---|---|---|
| A | Eight 1200 × 800 mm loads | Four rows, two across | 4800 × 1600 mm |
| B | Eight 1200 × 1000 mm loads | Four rows, two across | 4800 × 2000 mm |
| Combined | Sixteen actual loads | Zones placed consecutively | 9600 mm length before gaps |
| Unallocated region | No additional count claimed | 12032 − 9600 | 2432 mm length before exclusions |
Add spacing at the group boundary as well as within groups
For an illustrative 20 mm gap, each four-row zone needs 4 × 1200 + 3 × 20 = 4860 mm length. Two zones plus a 20 mm separation between them use 4860 + 20 + 4860 = 9740 mm. Euro rows need 2 × 800 + 20 = 1620 mm across, while industrial rows need 2 × 1000 + 20 = 2020 mm. This arithmetic counts the boundary gap once. Running zones independently without adding their shared boundary separation would understate the combined requirement.
If an agreed 50 mm wall band applies on every side, the usable region becomes 11932 × 2252 mm. The 9740 mm total length and both row widths fit that example region. Position the first zone after the front wall band and keep both within the side bands. These spacing values demonstrate how to make a record; they are not recommended loading or airflow allowances. Substitute the actual operation’s requirements and document any door-only reserve or irregular obstruction separately.
Why averaging dimensions gives an unreliable answer
The arithmetic average width of these two nominal groups is 900 mm because the quantities are equal. Sixteen fictitious 1200 × 900 mm loads preserve the total bare footprint area, but they do not preserve the actual packing problem. A 900 mm rectangle can fit a residual strip that cannot accept a 1000 mm load, while an 800 mm load may exploit a strip unavailable to the average. Packing depends on individual dimensions and orientation, not only total area or an average envelope.
Likewise, a quantity-weighted average height or mass can hide the tallest and heaviest units. Every load must meet its relevant envelope, and weight distribution requires the actual pallet list. Keep group-level quantities only where the members genuinely share dimensions and properties. If wrap, protective boards or partial loads create different envelopes, record those units separately. The convenience of one representative pallet should not conceal a shipment whose critical dimensions vary across the cargo.
Run each identical group within its allocated region
For the zero-gap example, enter a custom 4800 × 2352 mm region and a 1200 × 800 mm footprint for Zone A. Then enter the same region dimensions with a 1200 × 1000 mm footprint for Zone B. Review the returned candidates as zone-specific evidence. The known shipment only requires eight of each group; a larger zone capacity does not mean you should add more cargo without revisiting order quantity, mass and the combined boundary geometry.
The engine uses finite mixed-strip enumeration and multiple MaxRects rules for identical rectangles. A zone result marked best found remains a heuristic candidate, not proof of global optimality. Even an optimal result for each independent zone does not prove the combined zoning is optimal, because the chosen boundary may exclude better arrangements. Keep the scope in the record: two zone candidates for one proposed mixed shipment, with their specific coordinates translated to the combined floor drawing.
Make a mixed shipment worksheet
List each actual pallet group and quantity with the completed footprint, height and gross mass. Draw nonoverlapping zones with explicit origin coordinates and dimensions. Count within-zone gaps, between-zone separation and perimeter exclusions. Run one identical-size calculation per zone and translate its coordinates by the zone origin. Check that the combined rectangles remain inside the accepted floor and that no zones or pallet envelopes overlap.
Write your own input record beside this example: equipment identifier; dimension source and date; actual loaded footprint; rotation; gap; wall clearance; loaded height; result count and proof status. Retain the record with the layout.
Let loading sequence influence the zones
If the industrial pallets are needed first at destination, placing them at the closed end may create an access problem despite a valid final arrangement. Order the groups according to the unloading and handling plan, then revisit distribution and restraint. The geometry engine does not know stop sequence, commodity identity or fork-entry direction. A tighter combined arrangement might be less practical than the explicit zones, while an access channel might be necessary even if the door-side group can fit without it.
Heavy groups also need a separate distribution review. The difference between eight light Euro loads and eight dense industrial loads is absent from their rectangular footprints. Give the responsible reviewer both the cargo masses and the proposed coordinates. Do not claim the shipment is balanced because the two zone lengths are equal. Review the assigned equipment’s payload and local loading conditions, and confirm the loading method can place each group in its proposed location.
Know when a more detailed solution is required
Zoning is most useful when the order fits comfortably in a transparent construction or when grouping supports delivery and handling. If a tight shipment fails this simple plan, that does not prove no combined arrangement exists. Request a purpose-built mixed-size solver or a reviewed loading drawing rather than forcing both types into the identical-rectangle interface. Keep the quantities fixed during comparison so the proposed improvement concerns the same shipment.
Use the equipment’s actual floor and doors when finalizing the proposal. A nominal forty-foot class is not an assigned measurement, and standard, pallet-wide and refrigerated equipment must not share dimensions by assumption. The output of this workflow is a candidate arrangement with visible assumptions and unambiguous cargo identity. Its documented limits make it useful for operational review without presenting the zoning shortcut as an unsupported guarantee or mathematical maximum.
Primary sources and scope
EPAL Euro pallet: Reference footprint for the Euro group; finished envelopes are measured separately.
Hapag-Lloyd forty-foot Standard: Representative equipment context, distinct from the site’s historical preset and the assigned unit.