Now that I've drawn about 8km of survey the last scrap (top right hand corner - scrap bmb3_s3) has had 'pillar failure' again.
There are 3 pillars which do not work (the insides are filled). They are all walls with -outline in and I've tried reversing them, but it seems to stay broken. What's going on?
There is another problem. Even if scrap boundary has correctly specified all -outline out/in/none options, there may be problem to determine which area is inside of the scrap if the outline crosses itself (like figure 8). In such a case you get a MetaPost warning Warning: scrap outline intersects itself in bmb3_s3@fake and it is than random if MetaPost determines the interior of scrap correctly. The solution is to 1) find where the loop occured -- this may be tricky, but start with the endpoints where scraps should join. The loop may be very small, even unnoticable. Even worse, it may not be visible at all, because it happens anly after the joining of scraps -- which is the case of your example :( 2) correct the position of the control points (see the second picture) I hope the enclosed pictures make it more clear. Regards Martin