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How to draw a closed ring with rodCreatePath

patschouly

Hi,

I'm trying to build a guardring pcell using rodCreatePath(). However, when the start and end points are the same (a closed ring) the path disappears. The CIW informs me that the "master path [can ] not [be] created because it would be self-intersecting". I'm at loss here. When I'm creating a path in the layout editor (with the end type set to "extend"), I can do exactly this. This fails however with rodCreatePath (but only when the start and end point are on the corner of the ring).

What can I do to solve this?

Here's the code:

rodCreatePath(
    ?layer list("active" "drawing")
    ?width width
    ?endType "extend"
    ?pts list(
        0:0
        length:0
        length:height
        0:height
        0:0
    )
)

Parents
  • mbracht

    Hi,

    I don't think you can do that in the layout editor. If you start to draw your path a 0:0 and then place your last point again at 0:0 then that last point will actually become (0:0+width). Try it out,- create such a path in VLE and then look at it's point in the property editor. So this is not a rodCreatePath(..) issue, it's simply something a path doesn't allow.

    Max

Reply
  • mbracht

    Hi,

    I don't think you can do that in the layout editor. If you start to draw your path a 0:0 and then place your last point again at 0:0 then that last point will actually become (0:0+width). Try it out,- create such a path in VLE and then look at it's point in the property editor. So this is not a rodCreatePath(..) issue, it's simply something a path doesn't allow.

    Max

Children
  • Andrew Beckett
    in reply to mbracht

    Max is right - the path would be re-entrant (self-overlapping). You can draw it using this:

    rodCreatePath(
    ?cvId cv
    ?layer list("active" "drawing")
    ?width width
    ?endType "extend"
    ?pts list(
        0:0
        length:0
        length:height
        0:height
        0:width
))

    Note the final coordinate is slightly different to allow for the extensions and to avoid the overlap.

    Andrew.

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