Le modificateur Normal Edit

The Normal Edit modifier affects (or generates) custom normals. It uses a few simple parametric methods to compute them (quite useful in game development and architecture areas), and mixes back those generated normals with existing ones.

Options

../../../_images/modeling_modifiers_modify_normal-edit_panel.png

Modificateur Normal Edit.

Mode
Radial
Aligns normals with the (origin, vertex_coordinates) vector, in other words all normals seems to radiate from the given center point, as if they were emitted from an ellipsoid surface.
Directional
Makes all normals point (converge) towards a given target object.
Target Object

Uses this object’s origin as reference point when generating normals.

Optionnel dans le mode Radial, obligatoire dans le mode Directional.

Parallel Normals

Makes all normals parallel to the line between both objects” origins, instead of converging towards target’s origin.

uniquement pertinent en mode Directional.

Offset

Gives modified object’s origin an offset before using it to generate normals.

Uniquement pertinent en mode Radial si aucun Target Object n’est défini, et en mode Directional quand Parallel normals est fixé.

Mix Mode

Mix Mode

La manière d’affecter les normales existantes avec celles nouvellement générées.

Note that the Multiply option is not a cross product, but a mere component-by-component multiplication.

Mix Factor
Le niveau avec lequel les normales générées seront mélangées dans celles existantes.
Vertex Group
Allows per-item fine control of the mix factor. The vertex group influence can be reverted by using the small « arrow » button to the right.
Max Angle
Forbids new generated normals to have an angle to the original normal above that given threshold. This is useful to prevent extreme changes, that can even lead to inverting the front/back sides of a face, and consequently to ugly shading artifacts.
Lock Polygon Normals (padlock icon)
Prevents flipping (reversing front/back sides) of polygons which normal does not match anymore the side to which point its corners” custom normals. Can also help avoiding shading issues.

Utilisation

This modifier can be used to quickly generate radial normals for low-poly tree foliage or « fix » shading of toon-like rendering by partially bending default normals…

The only mandatory prerequisite to use it is to enable the Auto Smooth option in Mesh properties, Normals panel.

Astuce

More complex normal manipulations can be achieved by copying normals from one mesh to another, see the Data Transfer Modifier. Some shading effects can also make use of the Weighted Normals modifier.

Exemple

../../../_images/modeling_modifiers_modify_normal-edit_example.jpg

Examples of editing custom normals to point towards a given direction, see example blend-file.

Le maillage d’arbre à gauche a des normales non modifiées, alors qu’à droite un modificateur Normal Edit est utilisé pour les plier vers la caméra. Cette astuce d’ombrage est souvent utilisée dans les jeux pour une fausse dispersion dans les arbres et autres végétations.