function pts = WP_find3pts(a,b,c,d)
%


pt1 = -d*[a,b,c];
if a==0
    pt2 = [1,-d*b,-d*c];
elseif b==0
    pt2 = [-d*a,1,-d*c];
elseif c==0
    pt2 = [-d*a,-d*b,1];
else
    pt2 = [d*a,d*b,-d-a*d*a-b*d*b];
end

dir12 = pt2 - pt1;
dir12 = dir12/norm(dir12);
R = CS5320_gen_R([a;b;c],pi/2);
dir13 = (R*dir12')';
pt3 = pt1 + dir13;
pts = [pt1; pt2; pt3];

tch = 0;
