What is the Keyword

What is the Keyword

Post by handy.madi » Fri, 16 Nov 2007 15:42:57

Dear all,

I am a computer graphics newbie,
I need to do something which I even dont know the keywords (what is

There are two lines in a plane creating certain angle each other, and
I am currently looking at those lines from line-of-sight
to the plane and decide that smallest angle between both lines is X

If I moved, so that my line-of-sight is no more perpendicular with
plane, I think X should be no more X, what kind of calculation needed
to decide new X ?

Handy Madinata

What is the Keyword

Post by Robbie Hat » Sun, 18 Nov 2007 21:44:01

Well, the *actual* angle will always be x. The *projected* angle
(projected onto the plane of your retina) may be different, larger or
smaller, depending on the relative orientation of the angles.
I don't know the formula off the top of my head. I could look it up in
an analytic-geometry textbook, I suppose; but then, so could you.
I'd recommend that, or asking this question in a math group,
such as "sci.math", because it doesn't really have anything *directly*
to do with computer graphics, so it's somewhat off-topic for this group.
(Maybe you'll get lucky and someone here will know the formula and
tell you. But I wouldn't bet on it.)

Robbie Hatley
lonewolf aatt well dott com
www dott well dott com slant user slant lonewolf slant


What is the Keyword

Post by Josef Moel » Tue, 27 Nov 2007 19:51:20

Not only is the angle of importance, but also the direction from which
you view the angle.

I'd venture to say the keyword is "projection", as what the OP is
looking for is a projection of an angle in 3d to a 2d plane.

These are my personal views and not those of Fujitsu Siemens Computers!
Josef Mlers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize (T. Pratchett)
Company Details: http://www.yqcomputer.com/