Why do I get two entirely different answers when I do and do not normalize my vectors. When I don't normalize them, they give me some very large numbers which aren't useful.

  • \$\begingroup\$ Does gamedev.stackexchange.com/questions/89831/… answer your question? \$\endgroup\$
    – Adam
    Commented Jul 15, 2021 at 0:18
  • \$\begingroup\$ Not really. I don't think he is explaining anything that is useful. \$\endgroup\$
    – Ryan Glenn
    Commented Jul 15, 2021 at 0:50
  • \$\begingroup\$ I may be biased, but in my answer I point out two specific uses for a dot product between non-normalized vectors: 1) if neither vector is normalized, you can still determine whether they face in broadly the same direction, or opposite directions, or if they're precisely perpendicular. This is useful if you want to detect which side of a plane an object is on, like whether a target is in front of the camera or behind it. 2) if one vector is normalized but not both, the dot product gives you the length of the projection of one vector onto the other, useful for change of basis or measuring depth. \$\endgroup\$
    – DMGregory
    Commented Jul 15, 2021 at 1:29
  • \$\begingroup\$ If you want help with a specific use of dot products, you should edit your question to show us how you are trying to use dot products currently, what results you're getting, and how those results differ from.what you want. With those details in hand, we can re-open the question for answers. \$\endgroup\$
    – DMGregory
    Commented Jul 15, 2021 at 1:31


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