The edging service is paid not by geometry but by the billing length — and it is always no less than the geometric one. The difference covers technological losses: the tape's lead-in and lead-out on the machine, trimming, waste. The formula depends on whether the edge is straight or curved.
A straight edge
For a straight side the billing length is built in three steps:
- Minimum length. If the side is shorter than the minimum (a company production parameter), its length is pulled up to that minimum. Very short edges are not billed «at zero».
- Waste percentage. A company-set waste percentage is added to the length.
- Edge stock. A doubled edge stock is added (stock on both ends) — the tape runs past the edge and is trimmed.
The result: max(length, minimum) × (1 + waste%) + 2 × edge_stock. All three values are the company's production parameters.
A curved edge
For curved edging (grooves, milling cuts) the calculation is simpler: the geometric length is multiplied by a curvature surcharge — length × (1 + curvature_surcharge%). Curved application is slower and more wasteful than straight, so a metre of curved edge «costs» more than a metre of straight. The surcharge size is set by the company.
Why billing ≥ geometric
Geometry is the «clean» length of the edged section. The billing length is always greater than or equal to it: the bare length gets the minimum, waste, stock or curvature surcharge added. In the project summary both numbers stand side by side — you see how far the «paper» metre diverges from the real one.
What this means in practice
Many small parts with short edges — the billing length is noticeably larger than the geometric one because of the pull-up to the minimum. Long straight parts — the difference is small. Curves — more expensive than a running metre of straight band by the surcharge amount.
Bottom line
The billing length is what is actually paid: a straight edge = minimum + waste% + edge stock, a curved one = length + curvature surcharge. All the coefficients are in the company's production parameters, and both numbers (geometry and billing) are visible in the project summary.