A part’s design complexity factor is used to calculate process time for Cleaning, Finishing, Shakeout, and Visual Inspection (see Cleaning Formulas, Finishing Formulas, Shakeout Formulas, and Visual Inspection Formulas). It is a number between the value of the cost model variable lowComplexityAdjustment (0.9 in starting point VPEs) and the value of the cost model variable extraHighComplexityAdjustment (1.3 in starting point VPEs).

aPriori determines a part’s complexity factor by considering the ratio of the part’s surface area to its volume. We refer to a part’s surface-area-to-volume ratio as the part’s modulus.

The complexity factor is determined based on an additional ratio: the ratio of the part’s modulus to the modulus of a canonical simple part with the same volume. We refer to this ratio as the modulus ratio. The greater the modulus ratio, the greater the part complexity.

The cost model divides possible modulus ratio values into ranges, and associates with each such range a complexity factor range. In starting point VPEs, the assoictation is as follows:

Note that any modulus ratio less than or equal to 0.9 maps to complexity factor 0.9, and any modulus ratio greater than or equal to 10.0 maps to complexity factor 1.3. In other cases, the calculation of the complexity factor involves linear interpolation within these ranges. For example, if the modulus ratio is halfway between the bottom and the top of a modulus ratio range, then the complexity factor lies half way between the bottom and the top of the corresponding complexity factor range.

In general, if the modulus ratio is a certain fraction of the way from the bottom of a modulus ratio range to the top of that range, then the complexity factor is that fraction of the way from the bottom of the corresponding complexity factor range to the top of that range.

The table below summarizes the thresholds that are used to define these ranges. The cost model variables lowComplexityAdjustment and optimumComplexityAdjustment specify thresholds for both modulus ratios and complexity factors. Note that any modulus ratio less than or equal to lowComplexityAdjustment maps to lowComplexityAdjustment, and any modulus ratio greater than or equal to extraHighModulusRatio maps to extraHighComplexityAdjustment.