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overlapping polygon checking command in encounter

vicky

 I would like to know is there a command that checked for polygon overlap. I need to check the overlap of a instance box with a power domain which is non rectangular in shape. I am trying to use this command "dbIsBoxOverlappingBox" which does not always give me the overlap correctly.

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  • This is a common area of complexity so I'm glad you raised the question...

    I don't think there are native commands to check for overlaps between polygons.  When I've done this in the past, I've always needed to decompose the polygons to boxes and then check for overlaps.

    Depending on the version of Encounter you're using and the object type you're querying, there are a couple of ways you might decompose the power domain polygons (which I believe are considered placement constraints, or you could traverse from a power domain to its associated placement constraint) to rectangles:

    • dbForEachConstraintBox might be helpful.  There is an example of using this command to decompose a rectilinear partition in the gifts directory in a script called "userBlockageUtils.tcl"
    • If you're using 8.1, dbGet would expose the boxes directly off the constraint:
      encounter 7> dbGet selected.bndry.boxes
      {{894.3 733.6 1057.98 773.92} {894.3 542.08 1122 733.6}}

    More info on getting started with dbGet can be found in this post in the Digital Implementation Blogs.

    Let us know whether this points you in the right direction or if a more complete example would be helpful.

    Thanks!
    Bob

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  • This is a common area of complexity so I'm glad you raised the question...

    I don't think there are native commands to check for overlaps between polygons.  When I've done this in the past, I've always needed to decompose the polygons to boxes and then check for overlaps.

    Depending on the version of Encounter you're using and the object type you're querying, there are a couple of ways you might decompose the power domain polygons (which I believe are considered placement constraints, or you could traverse from a power domain to its associated placement constraint) to rectangles:

    • dbForEachConstraintBox might be helpful.  There is an example of using this command to decompose a rectilinear partition in the gifts directory in a script called "userBlockageUtils.tcl"
    • If you're using 8.1, dbGet would expose the boxes directly off the constraint:
      encounter 7> dbGet selected.bndry.boxes
      {{894.3 733.6 1057.98 773.92} {894.3 542.08 1122 733.6}}

    More info on getting started with dbGet can be found in this post in the Digital Implementation Blogs.

    Let us know whether this points you in the right direction or if a more complete example would be helpful.

    Thanks!
    Bob

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