POV-Ray: Newsgroups: povray.advanced-users: vector perpendicular to axis

POV-Ray : Newsgroups : povray.advanced-users : vector perpendicular to axis		Server Time 1 Nov 2024 21:21:17 EDT (-0400)

From:
Subject: vector perpendicular to axis
Date: 6 Nov 2001 10:50:30
Message: <nb1gutgtllto7ntp7t5bsk8s32blhlp8tl@4ax.com>

Is it simplest and good way I choosed ?

I have two points describing axis. I want find vector perpendicular to this axis
but it is not important where it points. So, is it good way?

  #local Axis=vnormalize(P1-P2);
  #local Vect=(abs(vdot(Axis,x))=1?vcross(Axis,y):vcross(Axis,x));

ABX
--
#declare _=function(a,b,x){((a^2)+(b^2))^.5-x}#default {pigment{color rgb 1}}
union{plane{y,-3}plane{-x,-3}finish{reflection 1 ambient 0}}isosurface{ //ABX
function{_(x-2,y,1)|_((x+y)*.7,z,.1)|_((x+y+2)*.7,z,.1)|_(x/2+y*.8+1.5,z,.1)}
contained_by{box{<0,-3,-.1>,<3,0,.1>}}translate z*15finish{ambient 1}}//POV35

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From: John VanSickle
Subject: Re: vector perpendicular to axis
Date: 6 Nov 2001 15:36:08
Message: <3BE84A21.89D6E02@hotmail.com>


> 
> Is it simplest and good way I choosed ?
> 
> I have two points describing axis. I want find vector perpendicular to this axis
> but it is not important where it points. So, is it good way?
> 
>   #local Axis=vnormalize(P1-P2);
>   #local Vect=(abs(vdot(Axis,x))=1?vcross(Axis,y):vcross(Axis,x));

I use this:

#local vA=vnormalize(pE-pS);
#local vB=vnormalize(vcross(vA,<vA.y,vA.z,-vA.x>));

Unless pE=pS, vB will always be perpendicular to vA.

Regards,
John
-- 
ICQ: 46085459

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