Cell - User Properties, Save/Load to GDS

edited March 2017 in General

Hi Matthias,

I think the following functionality is not working as it should. Version 0.24.7.

  • Create a new layout including a top cell
  • Add a "User Property" to the cell, e.g., lukas, lukas
  • Configure "Layout Writer Options": Check ON "Write cell / layout properties (at the cost of compatibility)"
  • Save the GDS, either as binary, or as Text
  • Close GDS
  • Load GDS
  • Edit the User Properties. The previously defined one is missing. The properties list is empty.

I also open the text GDS, and find that it doesn't have the User Property I defined. Here is an example GDS:

 HEADER 600 
 BGNLIB 3/18/2017 0:03:27 3/18/2017 0:03:27 
 UNITS 0.001 1e-09 

 BGNSTR 3/18/2017 0:03:27 3/18/2017 0:03:27 

You can see the property "lukas" is missing.


  • edited November -1

    I believe GDS spec doesn't allow a string in the Key field.

    If you repeat your steps but put


    as the Key, and


    as the Value, it will work. The hash or pound mark in front of the number 3 means treat it as an integer.

    Still, perhaps this could be made more obvious.

    OASIS file format preserves any key and value, which I use a lot. Therefore I like OASIS better, but Matthias likes GDS :-)

  • edited November -1

    Hi David,

    yes, that's right. And of course that should be more clearly indicated.

    Actually the only format supporting user properties in all flavours is OASIS. GDS2 only supports properties with integer keys and string values (while everything will be converted to a string). LEF/DEF generates properties on reading (for example net names), but otherwise, all other formats can't handle user properties.



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