CODEWITHSUNDEEP
openglgraphics3dwavefront
Bluehand
Bluehand

Reputation: 63

OBJ File: Why are there so many normal indices in comparison to normal values?

So I am reading obj files and make lists to store the vertices, texture vertices, normal, vertex texture and normal indices. Testing this with a cube results in 8 vertices and 6 normals but there are 24 items in the normal indices list.

Can anyone explain why this is as I am a little confused right now?

Upvotes: 3

Views: 972

Answers (1)

Hugh Fisher
Hugh Fisher

Reputation: 2514

The OBJ format is designed for Gouraud shading, with one normal per vertex; rather than flat shading, one normal per polygon. Pick a cube face, go through the file data and write down the normal indices and normals. You'll see why.

Upvotes: 2

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