People and sensitive electronics traveling in space need protection from high energy radiation. Solid shielding materials are very dense.
I assume that a very small proportion of particles strike the craft at a right angle. My idea is to make some walls, bulkheads, floors, and unused interior volumes from honeycomb panels with cell walls containing energy-absorbing material, such as Hydrogen-loaded plastic. Some high energy particles would strike the cell walls one or more times and lose some energy with each strike. Smaller cross-sections and longer cells would get more strikes.
Spacecraft designers would "tune" each ship for it's mission parameters using honeycomb panels of various thickness and cell sizes, along with solid shielding, if needed.
The honeycomb structure might help dampen shock and vibration during liftoff.
Hydrogen-loaded plastic cells could be molded in thick (long cells) pieces, then cut to the ship designer's specification, then sandwiched between thin sheets of solid material. Some 3-D shapes could be achieved. I think this would be more practical than making molds for each desired thickness, while making it practical for designers to specify exact desired thickness. Large interior spaces could be filled with thick panels glued together.
Various types of fasteners are already available for use with honeycomb panels, which should make incorporating these panels into existing design much easier. Since honeycomb is used in some surfaces of military aircraft, there are experienced technicians for installation and repair. Both of these factors make it practical to replace panels that have been degraded by use before the next flight.