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Thread: Triangle normals

  1. #11
    Senior Member
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    Re: Triangle normals

    A "vertex" is not just a position. A vertex includes many attributes that make it unique, including position, normal, texture coordinate, color, etc.. It means that your mesh has 1668 unique vertices (position + normal).

  2. #12
    Junior Member
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    Jan 2011
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    Re: Triangle normals

    It is clear. But what is it when one position has more than one normal? What does it mean in 3D graphics?

  3. #13
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    Re: Triangle normals

    It means you have more then one vertex with coincident position.

  4. #14
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    Jun 2011
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    Re: Triangle normals

    Stupid question Marcus, but as a new user I am wondering what makes a vertex coincident? I checked out the wikipedia, but would like to hear from somebody with Collada experience who could maybe simplify the definition for me.

  5. #15
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    Re: Triangle normals

    Coincident vertices are ones that share the same position, e.g. a triangle with two vertices at the origin and one elsewhere results in a line. i.e. it's a degenerate triangle.

    The concept of coincidence can apply to all the vertex attributes (position, normal, color, texcoords, tangents, etc. etc.) if one is sorting vertices to remove all redundency from the set of vertices. Any single attribute of a vertex that is unique, that differentiates it from others for the purpose at hand, makes for a unique vertex.

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