The performance of gun and rocket propellants, which consist of energetic materials, is largely determined by their geometry and composition. Con- ventional production methods limit the performance by putting constraints on both. With additive manufacturing, or 3D-printing, there are signi- cantly fewer geometry constraints and together with the ability to combine multiple materials into a continuous gradient new performance optimization opportunities are created. In the current 3D-printing world it is possible to print single-material or discrete gradient multi-material objects by trans- lating a CAD model to printer instructions. This translation is done with slicer software that slices a 3D-model and outputs printer instructions in a G-Code le. This thesis looks at how an object with a continuous gradient can be printed. A modied version of the popular Cura slicing software is presented that can apply an approximation of a continuous gradient to an input model. The printer paths are simulated with the slicer software and ultimately printed using TNO's multi-material 3D-printer. While the print results show that energetic materials behave in such a dierent way than normal plastics that 3D-printing them it is not an easy task, printing a 3D-model with a multi-material continuous gradient is certainly viable.