Talk:Bitangent

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Mathematics rating:	Start Class	Low Priority	Field: Geometry
Please update this rating as the article progresses, or if the rating is inaccurate. Click to show/hide comments. Please add to or update the comments to suggest improvements to the article. neat article, needs expansion.--Cronholm144 09:23, 23 May 2007 (UTC)

Isn't a Bitangent by this definition the same as a secant line? How does it differ mathematically? Also, I've heard "bitangent" and "binormal" used interchangeably in the context of a graphics programming applications (such as parallax mapping). Is this idea at all related to the definition provided here? --Tim Ambrogi

Secant lines, in general, cross a curve twice. Bitangents have two points where they touch the curve but do not cross it. The article could do a better job of making this more clear; I will work on rewording it and linking to secant. —David Eppstein 21:54, 22 February 2007 (UTC)

Apparently, the graphics programming application refers to the fact that you need a surface normal and a surface tangent to represent a three-dimensional surface. However, there is a third vector generated through the cross-product of the normal and the tangent (called the binormal or bitangent, depending on your point of view). Perhaps there is another term for this binormal/bitangent vector? In any case, this other common use of the term "bitangent" probably warrants some disambiguation, unless there is some connection that I am unaware of. --Tim Ambrogi