For the PolyJet (Vero, Rubber-like, ABS-like), SLS (Nylon 12), MJF (PA12 Nylon), and SLA (Accura 25, Accura ClearVue) processes, we use a standard solid infill for 3D printing.
For FDM parts (PLA, ABS, PETG), we use a smart matrix infill. This 10-15% infill optimizes material cost, weight, and print time, while also retaining structural rigidity. We do not currently offer custom infill options for these materials - in most earlier stage prototyping scenarios, smart matrix infill is the best option regardless (cost and added lead time required for solid infill FDM generally outweigh any performance benefits). If you are looking for solid infill, we recommend PolyJet or SLS materials, as these materials end up with higher strength and faster lead times.