Curvature, thickness and ID maps

Curvature, thickness and ID maps are utility maps baked from a mesh alongside the normal map and ambient occlusion map. They are not shown in the final material. Instead, texturing tools read them as masks: Adobe notes that many filters and materials in Substance 3D Painter adapt to the geometry using these maps (Substance 3D Painter documentation: Bake Mesh Maps). A curvature map, for example, is "often used to damage edges of the geometry to simulate edge wear" (Substance 3D Painter documentation: Bake Mesh Maps).

#The common utility maps

#Curvature

Marmoset puts it plainly: "Curvature maps are useful for generating masks for scratches, recessed dirt, and other effects", and Toolbag bakes both convexity and concavity by default (Marmoset: The Toolbag Baking Tutorial). The bright edges drive edge wear generators, and the dark cavities drive dirt and grime. A curvature map baked from the high poly picks up every bevel and panel line, which is why it works best from a high-poly with real bevels.

#Thickness

The thickness map stores "the thickness of the 3D mesh" (Substance 3D Painter documentation: Bake Mesh Maps). Thin parts, such as leaves, ears or cloth edges, come out bright (Marmoset: The Toolbag Baking Tutorial). Artists use it mainly as a mask for light passing through thin surfaces (Marmoset: The Toolbag Baking Tutorial; ArtStation: Assassin's Creed Shadows: Foliage).

#ID maps

An ID map gives each material or part a flat colour so that you can select it with one click in Painter or Designer (Substance 3D Painter documentation: Bake Mesh Maps). Toolbag's Material ID output bakes "a unique color for each material assigned to your high poly objects"; if you need specific colours, Marmoset suggests assigning them as albedo and baking an Albedo map instead (Marmoset: The Toolbag Baking Tutorial). In ZBrush, polygroups often serve the same purpose.

#Position and world-space normal

Position maps are gradients across the asset. Marmoset calls the position map "a good source for generating texture masks", for example a colour or saturation gradient from bottom to top (Marmoset: The Toolbag Baking Tutorial). Normal maps in world or object space record facing direction, "an excellent source for generating directional masks", like dust on top of an object (Marmoset: The Toolbag Baking Tutorial). Painter's position map tells it where the top, bottom and sides of the mesh are, which generators use to place rust at the bottom (Substance 3D Painter documentation: Bake Mesh Maps).

#How to make one

#Substance 3D Painter

1. Import the low poly and open Texture Set Settings, then click Bake Mesh Maps (Substance 3D Painter documentation: Bake Mesh Maps).
2. In the Baker Settings window, load the high poly and enable the maps you need: Normal, World Space Normal, ID, Ambient Occlusion, Curvature, Position and Thickness (Substance 3D Painter documentation: Bake Mesh Maps).
3. Click Bake, then OK when it finishes (Substance 3D Painter documentation: Bake Mesh Maps). Painter connects the maps to the Texture Set, so generators and smart materials pick them up automatically.
4. Test with an edge-wear generator: if wear appears on every edge evenly, the curvature map is working; if it appears nowhere, the high poly may be missing bevels.

#Marmoset Toolbag

1. Name meshes with _high and _low suffixes, for example mymesh1_high and mymesh1_low; the Quick Loader sorts them into Bake Groups, and "The names are not case sensitive" (Marmoset: The Toolbag Baking Tutorial). See bake groups and exploded bakes.
2. Adjust the cage so that it just encloses the high poly (Marmoset: The Toolbag Baking Tutorial). See bake cage.
3. Enable the outputs: Curvature, Thickness, Material ID, Position and Normals (Object) (Marmoset: The Toolbag Baking Tutorial).
4. For Material ID, give each high-poly material a distinct colour, or bake an Albedo map if you need exact colours (Marmoset: The Toolbag Baking Tutorial).

#Blender

Blender's Cycles bake types are Combined, Ambient Occlusion, Shadow, Position, Normal, UV, Roughness, Emit, Environment, Diffuse, Glossy and Transmission (Blender Manual: Render Baking). Position "Bakes world-space position data into RGB channels", and the Normal type can bake in object space (Blender Manual: Render Baking). There is no curvature, thickness or ID bake type, so:

1. Set up Selected to Active with a cage or Max Ray Distance, as for a normal bake (Blender Manual: Render Baking).
2. Bake Position and Normal (Object space) directly (Blender Manual: Render Baking).
3. For an ID map, give each high-poly part a flat-colour material and bake its colour onto the low poly.
4. Bake curvature and thickness in Painter or Marmoset, or build them in a shader and bake that output.

#Video tutorials

#Written tutorials

#Use in recent games

• Assassin's Creed Shadows (Ubisoft, 2025). Foliage atlases baked in Substance Designer to masks for roughness, normals and translucency, with separate mask channels for seasonal colour and leaf damage (ArtStation: Assassin's Creed Shadows: Foliage).
• The Last of Us Part I (Naughty Dog, 2022). ID masks baked from sculpted rocks for Substance, with shared crevice dust across materials (ArtStation: River Rock Breakdown).

#In different tools

• Substance 3D Painter: bakes all the maps above in one window and feeds them to generators and smart materials (Substance 3D Painter documentation: Bake Mesh Maps). See smart materials.
• Substance 3D Designer: bakes the same maps and uses them in graphs, as in the Assassin's Creed Shadows foliage masks (ArtStation: Assassin's Creed Shadows: Foliage).
• Marmoset Toolbag: curvature, thickness, Material ID, position and object normals as bake outputs (Marmoset: The Toolbag Baking Tutorial).
• Blender: Position and Normal bakes; no dedicated curvature, thickness or ID types (Blender Manual: Render Baking).

#Further reading and watching