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Draw path

bharath2k4er

 Hi ,

           I am drawing path in virtuoso. Whenever i draw path in 45 degress, i will get the off-grid errors. Is there any script which will adjust the grid automatically when i draw path in 45 deg.??  I know that if i drw a polygon i will not get the error, but i wanted to path only because of its properties..

 

 

T hanks for your constant support,

Bharath. 

  • Hi Bharath,

    Try to use wire (pathSeg) to replace path. This will solve your issue.

     

    How

  • How,

    where can i find these option in a virtuoso layout editor? I never came accross this option? will it contain all the features of a path?

    --Bharath
  • It's under Create->Wire. This is assuming you're using IC613. If using IC5141, pathSegs do not exist. You didn't say which version you're using...

    Fundamentally it cannot be done with a multi-segment path; basic maths will tell you that. You could convert into a polygon and then snap to the grid (many utilities around to do that).

    Regards,

    Andrew

  • Hi Bharath,

    Instead of using 'path' to create path, you may use wire (pathSeg) to create the path as well. Wire (pathSeg) is a multi section of path, you can easily see the joining when you draw a pathSeg with bending. (support 45degree).

    Go to Create->Wire, or use binkey 'Ctrl Shift w'

    How

  • \o Program:        @(#)$CDS: icfb.exe version 5.1.0 11/21/2005 22:33 (cicln03) $
    \o Sub version:        sub-version 5.10.41_USR3.27.30 (32-bit addresses)

    This is the version i am using..I think this belongd to  "IC5141" version.

    Andrew as u said there is no wire option in my current version. and i knew that fundamentally it will be in the off-grid if i draw path in 45deg.  I am trying to generate a script which will adjust the path to near by grid when drawn in a 45 deg shape..

    Ex: my path width : 1.000um
          In 45 deg bend it will be 1.004 (adjusted to nearby grid)

    I am this because path has more option when compared to polygon. For example , you can mention the length and width.

    I know it will be tuff to program for this req., just hoping there will be a easy way to overcome..
    Thanks,
    Bharath.
  • Hi Bharath,

    Unfortunately you can't really do this path enlargening just for certain segments of the path, because paths have a common width for all segments. The alternative would be to have separate paths for each segment, but then you'll have problems with the ends overlapping (or leaving gaps). With pathSegs, octagonal ends are used to solve this problem, with some very careful adjustments taken care by the create wire command.

    However, in IC5141, there is a capability in te Turbo Toolbox (if my memory is correct) called "poly paths" (or something like this) which solves the problem by creating and editing like a path, but the shape produced is actually a polygon.

    Obviously with a polygon you only have the vertices to worry about, and not the centre line too, so it's easy to keep on grid.

    Best Regards,

    Andrew
  • Hi Andrew. I'd tried to use wire instead path , but it still not on grid. I have two different env , one is snap spacing 0.1 and the other is 0.01. Wire works well on 0.01 spacing env , but not good in 0.1 . It confuse me , is there any setting about the wire/path for grid? Thanks
  • Please do not append to the end of a thread from > 6 years ago, and please provide more information, there isn't really enough detail in your post to even understand what the issue is.

  • Thanks Lawrence - I was going to say the same thing about the old thread.

    Rather irritatingly, JH Shih emailed me directly with more information than was posted here. Given that I've never had any interactions with the company (he?) is from, and I can't really respond to direct questions from users the world over when I am only doing this in my spare time (which is rather limited currently), please don't think you'll get quicker responses by contacting me directly. You won't.

    Here was the detail:

    It really takes time when I want to create it. I am surprised that the problem have not yet been solved for so many years (it shows the question has been post last century) .
    I think maybe there is a easier way to solve it.
    Since everyone is not so care about the width on 45 degree, and you can separate the path created by "wire", just make the part on 45 degree bigger and fix grid.
    For example, I create a 2 width wire like Z shape, and the part of / will be off grid. If we(actually U Cadence) can make it a bit bigger to width 2.12132. Then, magic, the part of / will on grid and makes everyone happy.
    The part of / don't have to really fix width with orthogonal one. We still have to fix it on grid most of time.
    I think it's just a scrip problem. Get width W, get snap spacing X, do math ((W^2)/2)^0.5 = S , (rounds up Sx with X) = Sx . Use Sx to build new path.
    Can it be useful?

    Well, wires already do widen the width on the 45 degree segments. That's how the edge vertices end up on the manufacturing grid. If it didn't widen the track then, it would be impossible to meet the grid requirements (because the square root of 2 is an irrational number).

    The problem is that you seem to be expecting the edge vertices to be on the snap grid, which is not what happens. The snap grid is used for the points you digitise - i.e. the centre line. That's for your convenience when  you are drawing a set of shapes, wires, lines etc to ensure everything lines up OK. However, what is important for manufacturing is that the outer vertices (on the edges of the wire) are on the manufacturing grid (which is defined in the tech file). That's what matters - and so that's what create wire does. There's no manufacturing reason why the outer vertices need to be on the snap grid.

    Regards,

    Andrew

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