CODEWITHSUNDEEP
iosvectoropengl-esscenekit
Dummy307
Dummy307

Reputation: 187

Need help explain about normal vector SceneKit

I follow this article to create a custom SCNGeometry

http://ronnqvi.st/custom-scenekit-geometry/

I see it need normal vector for every vertex. I also see the document here https://developer.apple.com/library/prerelease/ios/documentation/SceneKit/Reference/SCNGeometrySource_Class/index.html

In my knowledge, I think 3 vertices identify one plane and one plane need only 1 normal vector. So each 3 vertices we need 1 normal vector. Then it will decrease data and calculations

Can anybody help me explain it? or may I confused something?

Upvotes: 0

Views: 993

Answers (1)

mnuages
mnuages

Reputation: 13462

specifying normals at the vertex level (instead of face level) leads to better looking models. For instance spheres can be modelled with a decent number of vertices and will look perfectly round when shaded. This is because the normal at each point is the mathematically correct normal. If you took the face normal, then you could easily see these faces with a standard shading.

Upvotes: 2

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