Quote - Just to be clear: you don't have to pass a mesh with a million polygons to Lux. You pass in the 50k mesh and your displacement map, and it generates the finer mesh internally (or so it looks, but I may be wrong). Every renderer that does displacement correctly has to have some kind of internal representation of a refined mesh with displacement applied.

But if polygons are created internally they must be rendered, so in the end it will render one million polygons and not 50k.
Displacement maps, bump maps, transparency maps and even texture maps are tricks to give good visual image while keeping the number of rendered polygon low.

Stupidity also evolves!