What are leather grades?
No two hides are alike, and no hide is the same all over. The butt and the area along the backbone are usually the firmest and cleanest; the belly and flanks are looser and stretch more; the neck often carries growth marks. Cutting rooms mark these areas as grade zones, so that visible parts come from the best leather and hidden parts use the rest.
There is no single industry scale: tanneries and manufacturers grade by letter or by number, each in their own way. Lescut uses letters. Leather with no zone drawn on it is prime, grade A; zones B to E are progressively lower grades, and a defect is leather no part may use.
| Grade | Where it often goes (an example) | In Lescut |
|---|---|---|
| A (prime) | Faces people see and touch: seat fronts, bag fronts, shoe vamps | Leather with no zone drawn on it |
| B | Visible but less exposed: inside backs, gussets, arm facings | Zones on a B layer |
| C | Sides and borders seen less often | Zones on a C layer |
| D | Hidden or backed parts: outside backs, strips, tabs | Zones on a D layer |
| E | The lowest usable leather, for parts nobody sees | Zones on an E layer |
| Defect | Nothing | Defect shapes, lines and points |
A part may sit on leather of its own grade or better: a part graded C may use A, B or C leather, never D. Our corner-sofa sample grades its 30 parts A to D the same way: back and seat panels A, outside back and hidden strips D.
Which hide defects matter?
- Holes and cuts, which no part may cover.
- Scars, scratches and brand marks, usually drawn as lines or shapes on the hide.
- Insect bites and tick marks, often drawn as points.
- Growth marks, wrinkles and loose areas, which are often better graded as a lower zone than marked as defects, so hidden parts can still use them.
In Lescut a closed defect shape is kept clear by the part outlines. Open defect lines, such as a scratch, and defect points are widened into small zones by the scanner profile’s defect margin (3 mm unless you set another), so the part edge keeps that distance.
How much gap do leather parts need?
The gap between parts, set in the nesting profile, is the clearance your knife or laser needs. The nest keeps it between every two parts, from the hide edge and from every defect, on top of the defect margin around marked lines and points.
On a knife table, parts are often nested edge to edge at a 0 mm gap. A cutter profile can then cut a straight edge that two parts share only once; curves are never merged. With a laser, keep a gap at least the width of the kerf.
How does a part get its grade?
A part gets its grade from a GRADE: text inside its outline, such as GRADE:B (or data-grade on an SVG outline), or from the parts table after import. A part with no grade needs prime leather.
Some parts need prime leather only where they show. Draw that area as a closed shape inside the part on a layer named for its grade, such as QZ_A or GRADE_B: the sub-zone must sit on leather of that grade, the rest of the part on leather of the part’s own grade.
How do you prepare the hide DXF?
Conveyor and camera hide scanners export one DXF per hide, with the outline, the defects and the grade zones on their own layers. Lescut reads common layer names without any setup:
| Layer name | Read as |
|---|---|
| Starts with HIDE, OUTLINE, CONTOUR, BORDER, BOUNDARY, SKIN, LEATHER or PERIMETER | The hide outline |
| Contains DEFECT, FLAW, SCAR, SCRATCH, BRAND, DAMAGE or REJECT | A defect |
| Contains HOLE or CUTOUT | A hole in the hide |
| Ends with ZONE_B, GRADE_B, QUALITY_B or Q_B (and C, D, E) | A grade zone |
| Contains INFO, TEXT, LABEL or ID | Hide information |
If your scanner names its layers differently, a scanner profile maps each of its layer names to one of these roles and sets the defect margin. Other layers are left out.
A text such as ID:H-2026-0011 on the information layer names the hide; without it the file name does. A COST: or PRICE: text gives the hide’s own price, for the lowest leather cost goal; otherwise its price is its area times the scanner profile’s default hide price per m².
Drawings are read in the units the DXF declares, millimetres when it declares none. If no layer holds an outline, the largest closed shape is used and you are told. An outline, hole or zone that crosses itself is refused with the place to fix it, since no nest can use it.
How do you prepare the parts file?
Draw each part as one closed outline, with its holes as closed shapes inside it, in DXF or SVG. Drill holes, notches, stitch lines, marks and text on layers named for them travel with their part into the cutting files and are never cut as outlines. Short text options inside a part set how it nests:
| Text inside the part | What it sets |
|---|---|
| NAME:seat-panel | The part’s name, on labels and in the report |
| QTY:2 | How many of it one set needs |
| GRADE:B | The lowest leather grade it may sit on |
| ROT:180 or ROT:90 or ROT:0,180 or ROT:ANY | How it may turn; ROT:0 keeps it as drawn |
| TILT:3 | A few degrees it may turn off each allowed angle (0 to 10) |
| FLIP:Y | Whether it may be mirrored |
A grain line on a layer named GRAIN sets the part’s starting direction, along the hide, and a part with a grain line but no ROT: turns only in half turns. In a DXF block, one outline owns everything inside the block. Frames, dimensions and notes go on layers an import profile leaves out.
How do complete sets, batches and shade lots fit in?
The parts file is one set: one sofa, one bag, one pair of shoes. QTY: says how many of each part a set needs, and the job says how many sets to cut. A set is only useful complete, so when the hides cannot hold the whole order, the nesting profile decides what comes first:
| Sets mode | When the hides run short |
|---|---|
| Prefer complete sets | As many whole sets as fit, then parts of further sets only in leftover leather of hides already in use, never on an extra hide |
| Strict complete sets | Whole sets only, each from hides of one shade group; the rest stays unplaced |
| Maximum utilisation | As many parts as fit, sets or not |
Every mode places the whole order when it fits, and every result reports how many complete sets were placed. A set comes from one batch unless the job allows sets to mix batches, so its parts match in shade and grain, and the job page shows yield, leftover and complete sets per batch.
Shade groups are set per hide on the batch page: hides with the same group label are one shade lot, an unlabelled hide is its own group, and a job can treat each batch as one lot instead. Groups only matter to strict complete sets.
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