Normal Edit Modifier

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

Options

Normal Edit Modifier.

Mode

Radial

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

Directional makes all normals point (converge) towards a given target object.

Target Object

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

Optional in Radial mode, mandatory in Directional one.

Parallel Normals

Makes all normals parallel to the line between both objects’ centers, instead of converging towards target’s center.

Only relevant in Directional mode.

Offset

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

Only relevant in Radial mode if no Target Object is set, and in Directional mode when Parallel Normals is set.

Mix Mode

Mix Mode

How to affect existing normals with newly generated ones.

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

Mix Factor

How much of the generated normals get mixed into existing ones.

Vertex Group

Allows per-item fine control of the mix factor. Vertex group influence can be reverted using the small «arrow» button to the right.

Max Angle

(Todo)

Lock Polygon Normals (padlock icon)

(Todo)

Usage

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 Auto Smooth option in Mesh properties, Normals panel.

Tips

More complex normal manipulations can be achieved by copying normals from one mesh to another, see the Data Transfer Modifier.

Example

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

The left tree mesh has unmodified normals, while on the right one a Normal Edit modifier is used to bend them towards the camera. This shading trick is often used in games to fake scattering in trees and other vegetation.