Plasteel is the primary structural material in high tech level societies in StarCluster. It is a transparent fluid which can be hardened permanently with radiation, foamed, and shaped. It can be made Active - that is, it can be programmed with shapes, and if a brain controls it, live nearly infinite morphing. Surface films over the plasteel can be actively colored - that is colored under arbitrary control, or programmed as a display. The film can also be actively textured, enabling arbitrary surface texture under live or programmed control.
Some things that Active Plasteel tech from StarCluster implies:
[*]Auto-conformal wings on aitcraft and shuttles, always able to take the optimal shape for the speed and flying quality wanted. Also wing warping rather than flaps and ailerons.
[*]Weapons which change shape to multitask - a rifle changing into a shotgun, for example.
[*]Jointless personal armor.
[*]Legged vehicles as simple as wheeled vehicles.
[*]Peristaltic pumping piping.
[*]Masks and clothing that move and change shape.
[*]Secret doors, windows, and caches that show no sign of their presence even to the best trained eye.
[*]Display panels thougher than steel, with active sirfaces
And since all plasteel - even structural, rigid plasteel - is naturally transparent, there is no structural difference between a wall and a window - even on a spaceship.