Code:
if (mouse_right) 
{
   vec_set (mouse_click, mouse_dir3d); 
   vec_normalize(mouse_click, 4000); 
   vec_add (mouse_click, mouse_pos3d); 		
   c_trace (camera.x, mouse_click, IGNORE_MODELS); 
   vec_set( mouse_click, target );
   ent_create ("position1.mdl", target.x, NULL);
}

I use Lite-c