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Why stream out with broken pieces?

richardyuan

When I deal with some layout with broken parts, I merge them into polygons (From image1 to image2). 

  

But I when I stream out, I find the merged polygons return to broken parts again. Why that happens and how can I fix that?

  • kb how
    Hi Richard, the polygon get break into pieces becoz of vertices supported in strmout command. By increase the vertices may helps, but not all. Using option -maxVertices (allow 5-4000). For your case, since you have round shape, im expecting even 4000 vertices may not able to fix your cases.
  • richardyuan

    Even the small circles broken into 4 parts? That's disappointing......

    Do you noticed that the original one-part circle keeps its integrity after stream-out.

    While for the 4-parts circles, even I merge them first in Layout, will break into 4 parts again after stream-out. That's very weird.

  • Andrew Beckett

    It's nothing to do with the size of the circle. Circles are converted to polygons in stream format, and even if they were converted to polygons inside Virtuoso, there is a default maximum number of vertices in a polygon for stream of 200. This was historically a limit in stream of 200 vertices, and so by default that limit is honoured.

    If you look in <ICinstDir>/doc/transrefOA/transrefOA.pdf (remove the OA bits if you're using IC5141), you''ll see an appendix called "Stream Format" (Appendix A in the version I looked at). This has a section called "Differences in Stream Format Versions", which covers what changed over time. Version 7 removed the limit for 200 points (in fact removed a number of the other limits too). This was a very long time ago indeed, so it's highly likely most stream format readers would have no problem with more than 200 points.

    In both IC5141 and IC61X there is an option on the options choices for the stream out interface which allows you to increase this limit. In IC616 you hit the Show Options button, and then go to the Geometry tab, where you can increase the "Max Vertices" option.

    Regards,

    Andrew.

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