//
public static CTrans FromAxis(RPoint pt, RPoint vec, double an)
{
an *= Math.PI / 360.0; // half in radians
RPoint T = RPoint.Zero;
RPoint C = pt;
double lR = vec.Dist();
double xc = Math.Cos(an), xs = Math.Sin(an);
vec.Mul(xs / lR);
QPoint R = new QPoint(vec, xc);
R.Norm();
// w=R^(-1)*(l-C)*R+C
T.Add(ref C);
QPoint QC = new QPoint(C, 0);
QC.LMul(ref R);
QC.RDiv(ref R);
T.Sub(ref QC.PT);
return(new CTrans(T, R));
}
public void Mul(double v)
{
PT.Mul(v);
R *= v;
}
