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Explain like I'm 5: Reflection Algorithm

Started by August 29, 2012 06:51 AM
12 comments, last by tom_mai78101 12 years, 5 months ago
Ok, I got it now. But, the diagram that Bacterius drew invokes my curiosity on this one.
bJaTt.png
If I were to figure out this one, my life is complete.

FIXED.
Dot product gives you a single scalar value, not a vector, as a result.
Easiest way for me to visualise it is that two normalized vectors pointing in the same direction give 1.0, pointing in opposite directions gives -1.0, and pointing parallel gives 0.0. When calculating the dot of two normalized vectors, the result is a fraction of "how much the same" are these.
It's also used to 'project' one vector onto another -- e.g. how big is B in the A-direction.
FFozs.png
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Ok, I got it now. But, the diagram that Bacterius drew invokes my curiosity on this one. I know that a dot product is a scalar. If we are to draw the scalar, how long would the scalar be, if we use the same unit of measurement for all vectors A, and B, along with the scalar.

A scalar is just a length, so you can represent it as a line in any direction (as a scalar has no direction) to scale with the length of other vectors in my diagram (so if vector V was 4 units long, then a scalar of 2 would be represented by a line 2 units long, in an arbitrary direction). It was just convenient to align the dot product's value next to the normal vector to make the diagram more readable.

“If I understand the standard right it is legal and safe to do this but the resulting value could be anything.”

Ok, thanks! Everything is complete now. :D

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