This post is about Normals in Blender. If you don’t know what a “Normal” is, it is basically the direction the 3D face/vertex is pointing. A lot of things use Normals. Normals determine things like the direction of an Emmitter Object, the way the Hair Strand will stand, and how the Cycles Glossy Shader with Fresnel will react to the object. It is easy to figure out which way a Normal is pointing.
Determining the direction of a Normal
1. Backface Culling: Backface Culling shows faces like they might be show in a game engine. If the normal is not pointing outward, the face will become invisible. To activate Backface Culling, just press ‘N’, the under the ‘Display’ header, check ‘Backface Culling’.
2. Display Normals: You can also display the Normals as little pink lines that stick out from the face (or vertex). The direction of the line is the direction of the Normal. To display Normals, press ‘N’ IN EDIT MODE and under the ‘Mesh Display’ header, you’ll see a Mini-header that says ‘Normals’. The first button will show normals of each vertex, while the second button will show the normals of each face.
Ways to fix broken Normals:
If you happen to have broken/reversed normals, there are many easy ways to fix and reverse the normal.
1. If you find that your normals are terribly inconstant, just press ‘Ctrl+N’, or press ‘T’ and press ‘Recalculate’ under the Normals header. Your normals should be mostly cleared up, if not, you can go in and flip each face manually. (See below)
2. To flip each Normal manually, select the face(s) that have broken Normals and go to the Toolbar (press ‘T’) and scroll down to the Normals header and press ‘Flip Direction’. Or you can select the face and press ‘Ctrl+F’ and ‘Flip Normals’.
Thanks for reading!