Bake Maps and Auto UVs

Crush can bake the original's detail onto the low-poly copy as texture maps. It connects the maps in the copy's materials, so the result looks right straight away.

The Bake section of the panel has two toggle buttons:

  • Normal Map — bakes the original's surface detail.
  • Base Color — bakes the original's vertex colors.

You can turn on one or both. Then click Crush as usual. After the crush, the progress bar shows "Baking" while the maps are made.

Normal Map

Bakes the original's surface detail into a normal map on the crushed mesh's UVs.

  • The crushed mesh uses its own smooth shading instead of the Keep Normals transfer. This is what game engines expect. Keep Normals is greyed out while Normal Map is on.
  • Normal Y picks the green channel convention. OpenGL (default) is for Blender, Unity and Godot. DirectX is for Unreal. A DirectX map still looks correct in Blender.
  • The normal map is saved as Non-Color data.

Base Color

Bakes the original's vertex colors (its active color attribute) into a base color map. Scans and ZBrush polypaint keep their color this way.

  • Objects without vertex colors are skipped, and the report says so.
  • An object whose color lives in image textures, with no vertex colors, only gets the normal map. Base Color is not baked from textures.

Auto UVs

Baking needs UVs on the crushed mesh. Most scans and AI models have none, so Crush makes them.

  • When: the original has no UVs, or Keep UVs is off.
  • How: the mesh is split into a few large, projection-based islands. Each island is flattened, given equal texel density, and packed with a margin that fits the map size.
  • Ask first: when an original has no UVs, Crush shows a dialog first: "No UVs to bake onto" with a Auto UV and Crush button. The dialog lists the objects that have no UVs. If Keep UVs is off, the crushed copy is unwrapped without a dialog.
  • The report lists how many UV charts were made for each object.

When baking, the borders of the UV islands are marked as seams and Sharp on the crushed mesh. This splits the smooth shading along the seams, so the normal map bakes without visible seams.

If the original already has UVs and Keep UVs is on, those UVs are used for the bake.

Overlapping UVs

A bake writes each pixel of the map once. If two faces share the same UV space (stacked or mirrored islands, common in game assets), they fight over those pixels and the map is wrong there. With Keep UVs on, Crush checks for this and the report says so: it names the objects and how much of their map overlaps, and suggests turning Keep UVs off so the crushed copy is baked onto new UVs.

Where the maps go

Save To has two choices:

  • Blend File Folder (default) — maps are saved as PNG files in the same folder as the .blend file. If the file is unsaved, the maps are packed into the .blend instead. The panel shows "Unsaved: maps get packed".
  • Custom Folder — maps are saved as PNG files in the folder you pick. A path that starts with // is relative to the .blend file.

Files are named <object name>_normal.png and <object name>_basecolor.png.

Size sets the map resolution: 512, 1K, 2K (default) or 4K.

How the maps are connected

  • Each crushed mesh gets its own copies of its materials, named <object name>_<material name>. Your original materials are not changed.
  • If the mesh has no material, Crush makes one.
  • The normal map goes through a Normal Map node into the Principled BSDF Normal input. The base color map goes into Base Color.
  • If an input was already connected in the copy, the old link is replaced. The report says how many inputs were replaced.

Viewport

Workbench cannot show textures or normal maps. If the render engine is Workbench, Crush switches the scene to EEVEE and puts Solid-mode 3D views into Material Preview. The report says when it did this.

See also Limits for what baking cannot do.