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get pcells within a polygonal area, hierarchically

caver456

We have a polygon (not rectangle) at the top level, and pcells within that polygon's area, at various levels of hierarchy.  We would like to read properties from all of those pcells.

A version of geSelectArea that would allow a start and stop level, instead of only selecting in the top level, would accomplish the goal.  dbGetOverlaps descends the hierarchy, and would work great if you could specify a non-rectangular search area.

Any ideas?

Thanks

  • geSelectArea can't support hierarchy, because you can't select hierarchical instances - so that wouldn't work.

    Probably what I would do is use dbGetOverlaps using the bBox of the polygonal area, and then transform the bBox of the instances found to the top level coordinate system, and then check whether they are in the polygonal area using the code in https://community.cadence.com/cadence_technology_forums/f/48/p/23921/1316116#1316116

    The benefit of the dbGetOverlaps is that it will do the gross filtering and return the hierarchical references, and then you can save the SKILL point checking to just the remaining instances.

    Andrew.

  • will give it a shot, thanks. Do you have a feel for whether it would be more optimal / less code than either 1) breaking the original test polygon into primitive rectangles , calling dbGetOverlaps for each, and combining the results, or 2) doing an initial dbGetOverlaps, then for each item in the return value, do a reverse dbGetOverlaps using the bBox of the pcell as the test area and seeing whether the original test polygon is in the return list?

  • I don't think I could guess, because it is likely to be highly dependent upon the size of the region and how many tiles it would need, as well as the number of pcell instances you're likely to find. Even if I knew that I'm not sure I could guess which is likely to be the most efficient. Given the fact that you have abPointInPolygon, I don't think it's much code. Similarly fracturing the polygon (which could be done with dbLayerTile or the abe functions) won't be much code, nor would doing the reverse dbGetOverlaps.

    I suspect that in most cases any one would do and it wouldn't be worth re-implementing the other ways to find out unless there are a huge number of instances to check.

    Regards,

    Andrew

  • Ok, thanks again, this will definitely get us up and running.

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