Ask HN: Can you help me find that 3D rendering engine?

It was on HN awhile ago, it was basically "part 2" of an unveiling of a 3d engine that was several years in the making.

This 3d demo was totally awesome... it rendered trees + water + rocks + buildings in real time, and as he would move the mouse, he would terraform the world, and the water, trees and stone would react to it.

He could also "grow" rocks and buildings and stairs.

It was insanely realistic, very cool, and now ive spent a good 1 hour looking for it and cant find it.