// adjust entity to the ground height, using a downwards trace
		if(c_trace(my.x,vector(my.x,my.y,my.z-5000),IGNORE_PASSABLE|IGNORE_ME) > 0)
		dist_down= my.z + vFeet.z - hit.z; // always place player's feet on the ground
		else
		dist_down = 0;	
		
	   
	   if((dist_down > 0))
		{
		 	
		 dist_down = clamp(dist_down,100,accelerate(speed_down,-nc_gravity * time_step,0.1));
		 
		}
		else
	   {
	   	//do the speed down to equal 0 so that he snaps to the ground
	   	speed_down = 0;
	   	if((dist_down + speed_down)> 0)
	   	{
	   		speed_down = - dist_down - 0;
	      }
	      if(key_space == 1)
	      {
	      	jump_target = jump_height * time_step;
	      }
       }
       if(jump_target > 0)
       {
       	speed_down = (sqrt((jump_target)* nc_gravity))*time_step;
         	
       	jump_target -= speed_down ;
        }