3D engine

does anyone know about 3d engine?What is it?

Hope someone can provide some information and if have any websites, hope can provide some.
many grateful thanks in advance

That a kindof generic question.
A 3d engine abstrahates from the simple polygons a modern 3d accelerator can render to an actual world. It handels big worlds, so it often has to do intelligent tricks to keep the polygon count per frame low enough to guarantee interactive frame rates. It handles special effects like explosions, it handels interaction with the world like collision detection. There exist 3d engines for indor worlds (quake3 3d engine, unreal 3d engine) space shooter and flight sims, for almost everything. So the great trick is either to make it more realistically than ever (carmacks attempt in doom3 3d engine) or make the world bigger and mix up multiple kinds of engines (halo?).
In my eyes a 3d engine does not provide user movement code. That is game code specific.

I’m not pretty convince with what I wrote.
In my eyes, a 3d engine is the most beautiful, most challenging art I can imagine.

Of course 3d engines are not limited to games… I focused a bit much on that…