What are normals?

When I watch material guides they sometimes talk about Normals but I have no idea what that actually is. I tried looking it up but I can’t seem to find any definition of what exactly a Normal is. Any help would be appreciated, thanks!

A normal is like a direction. Often when dealing with geometry and the surfaces of planes you will want to know which way the planes are facing so that the computer can do a bit of math in order to determine what to show on screen. In a simple sense a normal can be used to determine which way planes are ‘facing’ so that light and other things reflect correctly. In more complex cases normals can be altered per pixel for interesting results. Keep looking online, there is a good weeks worth of reading if you want to really get a deeper understanding of what normals are and what they can be used for.

A Normal is the direction that points outwards and perpendicular to a plane.

A Vertex Normal is usually the average normal of all faces it belongs to.
Here is a picture with vertex normals being shown in green.

A Face Normal is what people generally refer to indirectly when they refer to normals.
An easy way to visualize a face normal is imagine putting a cube on the plane/face you want the normal of. Once the cube is flat on the surface of the face, imagine a line starting from the center of the bottom of the cube touching the face and going through the top of this cube. That is the face normal.

You can bend normals to achieve complex lighting effects cheaply using a normal map. This page is a pretty good reference for all things normal maps.

http://wiki.polycount.com/wiki/Normal_map

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Thank you!

Thanks, I’ll check out that wiki!

Japanese Translation:

法線 (ノーマル) とは何でしょう?(翻訳/要約)