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Re: what is 'this looks bad'?


On Sun, Sep 08, 2013 at 07:42:55AM +0200, Lorenzo Marcantonio wrote:
> Neither have I. Still no response on the list, I assume I'll have to dig
> thru the code.

It's almost an easter egg (after the TEXT_SIZE/SIZE_TEXT of yesterday,
kicad is becoming full of suprises!). This is what gives the message:

    return wxString( _("This looks bad") );  ///< @todo check source code and change this comment

*Now* I know why nobody answered:P

>From the code it seems that piece of DRC works in this way: while
checking a track segment against every other segment, the first segment
is taken as reference and the second one is compared against the first.
The coordinate system is moved so that the reference segment is with the
start point on the origin and the end point on the positive X-axis.

In the parallel segments case (if their 'vertical' distance is not
enough to clear) it reduces to a range intersection problem (on the
X coordinates, obviously), if a conflict is suspected a finer check
taking in account the track end shape (the semicircle) is done.

Case 1: the start point is inside the reference range


Case 2: the end point is inside the reference range


Case 3: the segment straddles the reference range (this actually only
checks if it straddles the origin, because the other cases where already


Case 3 is the 'this looks bad' situation. We could change the message to
'tracks overlapped' or something like that. And the todo comment, too.

I'm pretty sure that was a legal track... but probably pcbnew
was correct anyway:D

Lorenzo Marcantonio
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