Ray Marching
Ray marching is a rendering technique used to generate images by walking along the path of a ray through a scene. As opposed to ray tracing which computes analytically the intersection of a ray with the geometry, ray marching steps along the ray in small increments, testing for intersections at each step.
Combined with signed distance functions (SDFs), instead of marching in small increments, the ray is marched by a distance defined by the SDF of the nearest object.
Usage in Computer Graphics
It’s the most used technique for rendering fractals, organic shapes, smooth surfaces, and other geometrically complex objects that are difficult to represent with traditional polygonal meshes. A lot of shaders on Shadertoy use it to render complex scenes in real-time using only a fragment shader.