Start with actual panel cut dimensions
A panel cut list should already include its joinery and the chosen width and height allowances. Do not subtract the door frame twice when you move from the door calculator into sheet planning. Imports copy the panel cut dimensions at that moment; changing a door later requires another import.
Stock is 48 × 96 inches. Width runs across the sheet and the 96 inch length is the grain axis. Plan different thicknesses, faces, grades or materials in separate runs. A rectangle that fits the outline is not proof that its veneer appearance or material properties fit the project.
| Input | Initial value | Meaning |
|---|---|---|
| Stock | 48″ (1219.2 mm) × 96″ (2438.4 mm) | Nominal rectangular sheet used by the planner |
| Saw kerf | 1/8″ (3.175 mm) | Space lost between separated parts |
| Edge trim | 1/2″ (12.7 mm) | Removed from every edge |
| Usable stock | 47″ (1193.8 mm) × 95″ (2413 mm) | Calculated after four edge trims |
| Example panels | 2 × 20″ (508 mm) × 30″ (762 mm) | Illustration only; replace or import |
| Grain / rotation | Locked / disabled | Allow rotation only for suitable parts |
Kerf, trim and grain are separate constraints
Measure the effective cut loss of the blade and process you intend to use. The initial 1/8 inch kerf is an example, not a saw specification. Edge trim cleans up the stock perimeter; it does not replace separating kerf.
Both a global permission and the part’s unlocked grain setting are needed before the planner can turn a rectangle 90 degrees. Leave parts locked where the panel face, grain or project design requires a particular orientation. Rotation exchanges the placed width and length; it does not change the required finished part.
Usable width = 48 − 2t
Usable length = 96 − 2t
Two parts side by side need w1 + kerf + w2.
Gross yield = total placed part area / (sheet count × 48 × 96) × 100%.Area alone does not prove a layout fits
Assume 1/2 inch trim per edge and 1/8 inch kerf. Two 20 × 30 inch panels can fit side by side in the 47 × 95 inch usable area: their combined width plus one kerf is 40.125 inches. Their 1,200 square inches of area occupy 26.04% of one gross 4×8 sheet.
Two locked 46 × 47.5 inch blanks have a combined area smaller than the usable sheet, yet neither a side-by-side arrangement nor a stacked arrangement fits: 92.125 inches exceeds usable width, and 95.125 inches exceeds usable length. In this rectangular example two sheets are needed.
A 60 × 20 inch blank cannot fit across a 47 inch usable width. If the project permits rotation, 20 × 60 can fit. Two such rotated blanks fit across with one kerf. If grain must remain locked, the failed orientation stays a failure.
| Requested rectangles | Placement check | Outcome for this example |
|---|---|---|
| Two 20 × 30 inch panels | 20 + 0.125 + 20 = 40.125 ≤ 47; length 30 ≤ 95 | One sheet has a feasible arrangement |
| Two 46 × 47.5 inch panels, grain locked | 46 + 0.125 + 46 = 92.125; 47.5 + 0.125 + 47.5 = 95.125 | They cannot share one sheet |
| Two 60 × 20 inch blanks, rotation allowed and grain unlocked | Rotated to 20 × 60; occupied width 40.125 | One sheet has a feasible arrangement |
Read the layout as a candidate cutting plan
The deterministic guillotine heuristic tries two sort orders and two split policies, then retains a candidate with the lowest sheet count among those attempts. It checks rectangle fit, kerf separation, trim boundaries and rotation permission. It does not search every possible arrangement or prove a global minimum.
Gross yield includes trimmed edges in the denominator. Usable yield excludes them. The remaining area includes cut loss and potentially unusable offcuts; it is not a promise of reusable material or zero waste.
Review every part quantity and sheet, confirm a workable cut sequence, and compare the first blank with the receiving assembly. Downloaded SVG diagrams and browser printouts are schematic; use the written dimensions rather than measuring a scaled drawing.
Frequently asked questions
Does this optimizer guarantee the fewest plywood sheets?
No. It uses a deterministic guillotine heuristic with four attempts. It produces a feasible rectangular candidate, not a proof of the globally smallest sheet count or zero waste.
Does the plan include saw kerf and edge trim?
Yes. Edge trim is removed from each of the four sheet edges. The entered kerf separates neighboring rectangles within each layout. Measure both values for your stock and process.
Why did an imported panel keep its grain locked?
Imported door panels start locked so they are not silently rotated. Turn on rotation and unlock the specific row only when its material, face and project requirements allow a 90 degree turn.
Can I mix MDF and plywood in the same run?
Use separate runs for different material, thickness, grade or face requirements. The planner packs rectangles; it does not verify that two rows may be cut from the same physical sheet.
Do imported panels update after I edit a door?
No. Import is a snapshot. Import the current door or saved batch again after changing the upstream cut dimensions, and review the replaced rows.
Sources and scope
- USDA Wood Handbook, Chapter 13 — dimensional change, equation 13–2 and table 13–5
Printed pages 13–15 and 13–16: species and radial/tangential coefficients, using moisture-content percentage points within the stated 6–14% range.
Worked examples are calculations under the stated assumptions. They are not physical test results or manufacturer approval of a finished assembly.