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Hi I am new to game development. I see many examples and tried myself like displaying triangle, cube etc. Now I am looking to render a Collada object. So I created a Collada object using Google Sketch up and trying to render that now. But the thing I am not understanding is, in all examples the vertices are between -1.0 and +1.0 values. But when I looked into that Collada file, the vertices were ranging from -30.0 to 90.0. I know any vertices greater than 1.0 will not display on iPhone. So can you pleas tell my the secret behind converting Object coordinate to normalized vector coordinate?

My previous triangle defined as

struct Vertex{

    float Position[3];
    float Color[4];
};
const Vertex Vertices[] = {
    {{-0.5, -0.866}, {1, 1, 0.5f, 1}},
    {{0.5, -0.866}, {1, 1, 0.5, 1}},
    {{0, 1}, {1, 1, 0.5, 1}},
    {{-0.5, -0.866}, {0.5f, 0.5f, 0.5f}},
    {{0.5, -0.866}, {0.5f, 0.5f, 0.5f}},
    {{0, -0.4f}, {0.5f, 0.5f, 0.5f}},
};

And now triangle from collada is

const Vertex Vertices[] = {
    {{39.4202092, 90.1263924, 0.0000000}, {1, 1, 0.5f, 1}},
    {{-20.2205588, 90.1263924, 0.0000000}, {1, 1, 0.5, 1}},
    {{-20.2205588, 176.3763924, 0.0000000}, {1, 1, 0.5, 1}},
    {{-20.2205588, 176.3763924, 0.0000000}, {1, 1, 0.5, 1}},
    {{-20.2205588, 90.1263924, 0.0000000}, {1, 1, 0.5, 1}},
    {{39.4202092, 90.1263924, 0.0000000}, {1, 1, 0.5, 1}},
};
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the units depend on how you export or scale your collada object, and how your renderer interprets those values. what values do you expect, or what were the values for our cube for example? –  cppanda Dec 22 '12 at 17:50
    
@cppanda I updated my question –  rakeshNS Dec 22 '12 at 19:13
    
it seems to me that you simply made a larger triangle in Google SketchUp. You can just scale it down and export it again to receive smaller values. I think your last sentence about normalizing is just a misunderstanding. Normalizing any object coordinates to be between 0 and 1 is not something you have to do. depending on the view and perspective setup a different range of coordinates will be shown on screen, those could be from -1 to 1, from -30 to 100, this really depends on your "camera" –  cppanda Dec 22 '12 at 23:50
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