An additive-manufacturing machine cannot directly execute an arbitrary solid model. The geometry must be converted into a sequence of build instructions.

Slicing intersects the model with successive layer planes. Each slice defines the regions that must be created at one build height. Toolpaths, scan vectors or exposure regions are then generated from those cross-sections.

Layer thickness creates a geometric approximation. On a sloped surface, finite layer height produces a stair-step effect. Thinner layers can reduce this discretization but increase the number of layers and therefore often increase build time.

Build orientation changes several things at once:

• which surfaces show stair stepping;
• the amount and location of support material;
• heat-flow or curing history;
• accessible removal paths;
• mechanical anisotropy relative to service loading.

Some processes need supports beneath overhanging or weakly anchored regions. Supports can prevent collapse, resist thermal distortion or conduct heat, but they consume material and require removal.

For example, rotating a bracket may reduce support volume but place its most accurate hole axis in a less favorable orientation. The best orientation is therefore not simply the one with the shortest build height.

Digital preparation is part of manufacturing process planning: geometry, orientation, slicing and supports determine the physical history of the final part.