ENTITY* grindblock;
ENTITY* current_rail;
VECTOR* grindtrace = {x=0; y=0; z=0;}
VECTOR* grindheight = {x=0; y=0; z=0;}
VECTOR* grindtest = {x=0; y=0; z=0;}  

[...]


void movement_state_grind()
{
   
   if(grindblock == NULL)    // has the block already been created? If not, create it
   {
      grindblock = ent_create("grindblock.mdl", nullvector, NULL);
      set(grindblock, TRANSLUCENT);
      set(grindblock, PASSABLE);
      grindblock.alpha = 0;
   }
   vec_set(grindblock.x, nullvector);
   grindblock.x = 1;
   vec_rotate(grindblock.x, player.pan);   // take into account the player's angles
   vec_normalize(grindblock.x, 3);         // place it 3 quants in front of him (speed = 3 quants per frame for testing)
   vec_add(grindblock.x, player.x);        // the final position of the block
   vec_set(grindblock.pan, player.pan);    // to make sure the block and the player are facing into the same direction
   vec_set(grindtrace, nullvector);
   grindtrace.z = -1;                      // trace downwards
   vec_rotate(grindtrace, grindblock.pan); // "downwards" is relative - rotate it and align the angle to the player angle
   vec_normalize(grindtrace, 100);         // trace 100 quants downwards (should always be enough to hit the rail)
   vec_add(grindtrace, grindblock.x);      // final position of the trace target
   me = grindblock;
   you = player;
   c_trace(grindblock.x, grindtrace, IGNORE_ME|IGNORE_YOU|IGNORE_PASSABLE|USE_BOX);  // ignore the grindblock itself and the player
   vec_set(grindtest, target);
   if(you == current_rail)
   {
      if is(your, FLAG3)
      {
         vec_set(grindheight, nullvector);
         grindheight.z = -1;
         vec_rotate(grindheight, player.pan); 
         vec_normalize(grindheight, -47);       // go up 47 quants from the target vector to get the new position of the player model
         vec_set(move_reldist, nullvector);     // no relative movement
         vec_diff(move_absdist, target, player.x); // absolute movement is the difference between current and new absolute position
         vec_to_angle(player.pan, move_absdist);   // force the player to look into that direction
         vec_add(move_absdist, grindheight);       // add in the 47 quants for player hight
      }
   }
   else
   {
      player_movement = falling;        // if the rail was NOT hit, the end of the rail has been reached (most likely ^^')
   }
   
}

c_move(player, move_reldist, move_absdist, IGNORE_PASSABLE|GLIDE);

ENTITY* grindblock;