Configuration experts know the 150% BOM inside out. But few can name the two other methods that exist alongside it — and know when to use which.
Subtractive configuration
The 150% BOM is the backbone of most ERP-driven configuration: you start with every conceivable option and then remove whatever the specific variant doesn’t need. That is subtractive configuration — and anyone who has worked in automotive or industrial plant engineering often knows only this one method.
Full definition in the glossary
But there are two other fundamental methods, and complex products often need all three.
Additive configuration
You start from zero and combine standardized modules through defined interfaces — Lego logic: the building block itself is trivial, the interface is what matters.
Parametric configuration
Here, no parts are selected at all. Instead, you define the product through parameters — dimensions, capacities, geometry — and let the concrete values determine the shape. This is exactly the foundation for design automation.
One product, several methods
A single product can easily use more than one method: additive for its modules, parametric for length-adjustable parts, subtractive for the order logic on the ERP side.
I’m also sketching a possible fourth method that doesn’t fit neatly into any of these three. More on that in a future post.
Subtractive, additive and parametric configuration are not competing approaches but a toolbox. Complex products often use all three at once — depending on which product area is being modeled.
