aPriori provides several cost models for user-guided costing, which allows you to cost a virtual part, a part for which you do not have a CAD model. With a GCD-driven cost model, aPriori extracts from the CAD model geometric information about the part. With a user-guided cost model, in contrast, the user enters certain basic pieces of geometric information (such as part volume and the dimensions of the part’s bounding box, among other values). This section introduces user-guided costing. Separate chapters provide details on each user-guided cost model (Injection Molding, Progressive Die, Stage Tooling, and Turret Press).