my.z -= c_trace(my.x,vector(my.x,my.y,my.z - 4000),IGNORE_ME|IGNORE_PUSH|IGNORE_PASSABLE|IGNORE_SPRITES|USE_BOX);

...

vec_set(temp,my.x);
temp.z -= 4000;
result = trace(my.x,temp,IGNORE_ME|IGNORE_PUSH|IGNORE_PASSABLE|IGNORE_SPRITES|USE_BOX);


...
 
result = trace(my.x,vector(my.x,my.y,my.z - 4000),IGNORE_ME|IGNORE_PUSH|IGNORE_PASSABLE|IGNORE_SPRITES|USE_BOX);
player_ground_dist = result;