Ray Marching is a rendering technique used to generate complex, detailed scenes by iteratively 'marching' a ray through a scene until it hits an object or reaches a predefined limit. ray marching calculates the distance from a point in space to the nearest surface (using a Signed Distance Function or SDF ) and steps through space incrementally.

In Three.js Ray Marching isn't a built-in feature, but you can implement it using custom shaders written in GLSL.