AI & 3D generation · Advanced

Signed distance field

A shape stored as the distance from every point in space to its surface

Also called SDF

What is a signed distance field?

A signed distance field, or SDF, describes a shape by storing, for every point in space, how far that point is from the shape’s surface. The sign says which side: positive outside, negative inside, zero exactly on the surface. It gives smooth, watertight shapes that blend easily, and many AI 3D tools use one before making a mesh.

Think of it like this

It is like a depth chart of a lake: every spot is a number, positive on land and negative in the water, and the shoreline is where it reads zero.

Where it fits in a 3D project

  1. Create
  2. Surface
  3. Rig
  4. Animate
  5. Render
  6. Export

Create: Building the shape: modeling, sculpting, scanning or generating it.

How a signed distance field works

  1. 01Space is filled with sample points, often on a grid.
  2. 02Each point stores its distance to the nearest surface, negative if it sits inside.
  3. 03The surface is wherever that distance is exactly zero.
  4. 04An algorithm such as marching cubes turns that zero level into a mesh.

Signed distance field vs mesh

PropertySigned distance fieldMesh
StoresDistances through spaceVertices, edges and faces
Blending shapesSmooth and easyNeeds booleans or remeshing
Sharp detailSoftens at low resolutionKept exactly
Used forAI 3D, crisp text, effects, collisionsAlmost everything in 3D apps

A mesh is what you edit and export; an SDF is a working format, used where smooth blending or inside-or-outside tests matter.

Where a signed distance field is used

  • Turning AI 3D output into a watertight mesh
  • Smooth, blobby modeling and melting effects
  • Crisp text and icons at any size in games
  • Fast collision and distance checks in real-time apps

Beginner tip

You rarely edit an SDF by hand. If an AI-generated model looks melted or rounded at the corners, the field’s resolution was low; regenerate at a higher detail setting if the tool offers one.

Terms related to a signed distance field

Signed distance field FAQ

What does SDF mean in 3D?
Signed distance field: a way of storing a shape as the distance from each point in space to its surface. “Signed” means the number is positive outside the shape and negative inside it.
How are signed distance fields used in AI 3D?
Many AI 3D tools predict an SDF, or something like it, instead of building a mesh directly, because a smooth field is easier for a network to learn. A step such as marching cubes then turns it into the mesh you download.
Are signed distance fields the same as voxels?
Not quite. Voxels are a grid of small cubes that are full, empty or hold a value. An SDF can be stored on a voxel grid, but each cell holds a distance, which lets the surface fall smoothly between cells.

Updated October 29, 2026 · Browse all 3D terms