IUBio GIL .. BIOSCI/Bionet News .. Biosequences .. Software .. FTP

simple problem

M. Johan Broekman hanbroekman at compuserve.com
Wed May 17 18:35:50 EST 2000

Mark wrote:
> Given the cartesian coordinates of
> two points a and b in 3D space, I need the position
> of a third point c such that the angle c-a-b has a fixed
> value, say 104.5 degrees.
>           c
>            \
>             a - b
> how can I obtain the coordinates (x,y,z) of c from the
> known coordinates of a and b?
> Clearly there are many equivalent choices of c satisfying
> this requirement; what I'm looking for is simply the direction of some
> a-c axis which form the required angle with the a-b axis.
> is it a trivial problem? I haven't found a solution...
> any help appreciated
> Sent via Deja.com http://www.deja.com/
> Before you buy.

My very old, and rudimentary trig experiences suggest that there are an
infinite number of points "c", all laying on a cone shaped surface with
angle xyz from the line a-b.
Best regards
Han Broekman
(Please answer to the newsgroup)

More information about the Molmodel mailing list

Send comments to us at archive@iubioarchive.bio.net