Float:distance_to_ground( id )  { 
    new Float:start[3], Float:end[3], bool:bDucking; 
    entity_get_vector(id, EV_VEC_origin, start); 
    bDucking = (entity_get_int(id, EV_INT_flags) & FL_DUCKING) ? true : false; 
 
    end[0] = start[0]; 
    end[1] = start[1]; 
    end[2] = start[2] - 9999.0; 
 
    new ptr = create_tr2(); 
    engfunc(EngFunc_TraceHull, start, end, IGNORE_MONSTERS, (bDucking) ? HULL_HEAD : HULL_HUMAN, id, ptr); 
    new Float:distance; 
    get_tr2(ptr, TR_flFraction, distance); 
    free_tr2(ptr); 
 
    if( distance < 1.0 ) { 
        distance *= 9999.0; 
    } 
    return distance
}