LUKA is an alternative method of area calculations, most commonly used by the Dutch duct work industry.
Patterns equipped with LUKA Area Calculations
The table below details the CID Numbers which have LUKA Area Calculations.
| Pattern Class | CID Numbers |
| RectStraight | 1 25 36 410 411 340 412 |
| RectTaper | 2 27 342 440 441 |
| RectBend | 3 4 17 20 22 23 420 421 430 431 819 354 526 761250 251 |
| RectBranch | 7 417 |
| RectCapEnd | 12 802 401 222 127: |
| RectDropBend | 320 399 801: |
| RectOffset | 5 13 470 471: |
| RectRadiusOffset | 9 330 367: |
| RectRadiusOffsetIn3 | 939: |
| RoofKerb | 971: |
| RectSqrRnd | 8 28 29 34 450 451 324 254: |
| RectStrtBranch | 15 38 760 39 : |
| RectTee | 5 13 470 471 255: |
Applying LUKA Area Calculations
Two Fields in the Pattern Database - Options page are used to control the minimum area and minimum length allowed in the calculations. These are highlighted in red here.
The exact area calculation differs from fitting to fitting but in general:
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The maximum periphery is multiplied by the greater of the actual length and the LUKA minimum length.
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The area value returned is the greater of the calculated value and the LUKA Minimum Area.