So I’ve seen here and there tangents being used in 3D graphics. My question is, why? My first thought was that it may be something to do with lighting, because of how a tangent of a circle/plane is where a line touches, but not intersects it. So maybe it was used for not calculating light for a specific face behind another. Which could be done with basic shadow mapping… Then I thought it may have to do with shadow mapping… And now I’m just really confused…
I also know that it is the the length of the ‘opposite’ side divided by the length of the ‘adjacent’ side of a right angle’d triangle.
Pic:
- Does this have to do with calculating the edge of circles/planes from a point in space, but how? I’ve seen ‘models’ with a tangent component, and they weren’t calculated from a specific light point either.
TL;DR: What does tangents have to do with 3D models? And why/how/where should I use them?