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Erik23a86

Help me understanding vertors

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Erik23a86    122
Can anyone show me what the vectors of a triangle are with the co-ordinates (-3,-2), (-2,2), (-1,-1)? I just not know how the vectors a running and in wich direction they are pointing. I know how to calculate the vectors: Vector.x = Point1.x - Point2.x; Vector.y = Point1.y - Point2.y; If I do this I get a co-ordinate, but I don''t understand how this could be the correct vector. Please show me how it must be done (examples). Thanks. The One.

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psykr    295
What vectors do you mean? Do you mean the vertex normals? The face normal?
Your calculation seems to be the vector for one of the sides of the triangle..

Assuming that you''re looking for the face normal, you two vectors representing the sides of the triangle (you subtract point A from point B, then another pair, say point B from point C). Then you find the cross product of these two vectors, normalize it, and voilà, you have the face normal.

Agent Smith.

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Erik23a86    122
What are vectors exactly? I know that they have a magnitude and a direction, but what are they exactly? In science class I leared to see vectors as an arror that is pointing into a direction and that a vector has got a magnitude. Where and how do I draw the vectors (arrows) in a polygon, for example in a triangle? How must I picture the vectors in a triangle to myself?

Thanks.

The One.

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