Normals

Normals does two jobs, each with its own switch. It turns faces that point the wrong way back around, so the whole surface faces outward. And it sets how the mesh shades: fully smooth, or smooth with hard edges wherever two faces meet at a sharper angle than you choose.

What it does

Fix winding. Every face has a front and a back, set by the order of its corners. A face turned the wrong way shows its back, drawn red in the viewport, and a game engine may not draw it at all. AI-generated models, Boolean cuts and hand-made shapes sometimes end up with a few such faces. Fix winding turns them around:

A closed piece, such as a box or a character, ends up facing outward.
An open piece, such as a sheet or a cloth, keeps the way most of it already faces. A small patch that faces the other way is turned to match, never the rest.

The stats strip under the parameters counts the edges where the faces disagree. After Normals that count is 0. When it turns faces, the node shows an amber note saying how many, for example Normals flipped 18 faces in 4 pieces.

Smoothing. The smoothing angle decides which edges shade hard:

180° (the default) shades the whole mesh smooth. Use it for organic models, and for any model that gets a baked normal map, which adds the fine detail back.
30° or so gives a hard-surface look: curved parts shade smooth and sharp corners stay crisp.
0° shades every face flat.

The viewport and the exported file both show the shading exactly as the node sets it.

Before baking: hard edges need UV seams

If you bake textures later in the chain, every hard edge must sit on a UV seam, or the baked normal map shows a crease along it. Keep smoothing at 180° for a baked model, or put Normals before Auto Unwrap, which prefers to put its seams along the hard edges it finds. Check that every hard edge landed on a seam before you bake.

Where to put it

Put Normals after the nodes that reshape the mesh, because Subdivide, Boolean, Remesh, Noise and Inflate all work out their own shading. Put it before texturing: turning a face after a texture is baked or painted flips that face’s relief. In the AI cleanup chain it sits after Clean and Polyreduce, and before Auto Unwrap and Bake.

Only part of the mesh

Set Apply to to a named selection to change only those faces. The node still judges which way is out from the whole surface. Selecting a patch that faces the wrong way turns just that patch, and a selection that leaves the wrong faces out turns nothing. Smoothing a selection blends it into the faces around it, so a selection smoothed the same way as its surroundings shows no seam.

What stays the same

Normals never moves a point or adds a face. UVs, vertex colours, materials, part names and selections all stay. When you export an imported model, only the parts Normals changed are rewritten.

Inputs

Mesh

The mesh whose normals to recalculate.

Outputs