% makes a line according to parametric form: point P and vector v
% 

function linepar(P,v,xmin, xmax); 
   
tmin = (xmin - P(1))/v(1); 
tmax = (xmax - P(1))/v(1); 

 Pmin = [xmin, P(2) + v(2)*tmin, P(3) + v(3)*tmin]; 
 Pmax = [xmax, P(2) + v(2)*tmax, P(3) + v(3)*tmax]; 
 
 lineOM(Pmin, Pmax); 
 plot3(P(1), P(2), P(3),'*');