pdaLayoutGdsSettings

Structure

This element does not have attributes. The elements are shown below, in a sorted per type fashion.
In case a list is printed after an element, it indicates that you can have many, otherwise it should be a single element. With a optional it tells the element is not required.

<pdaLayoutGdsSettings> ...
  <cellname_style> ... </cellname_style>    optional
  <cellparameter_prefix> ... </cellparameter_prefix>    optional
  <cellparameter_style> ... </cellparameter_style>    optional
  <cellport_style> ... </cellport_style>    optional
  <polygonSize> ... </polygonSize>    optional
  <wireSize> ... </wireSize>    optional
</pdaLayoutGdsSettings>

XSD

The schema file can be downloaded or viewed at xPDK_Layout.

Details

cellname_style

Define how the GDS cell name should look like for parametric cells.

The purpose of this field is to for BBs which have parameters - it is therefore likely that multiple versions of this BB are in a gds cell, often with different parameters values, for example a modulator with length=100 and one with length=200. In the design kit this can be handled by a single name, like fab_modulator, with a parameter - basically the parameteric cell (pcell) approach.
In GDS / Oasis this option is not there - you can not evaluate the parameters and related logic without the design kit / software. So you need a name + something set up for this. That's what this field is for.
There is no standard on this topic, so a few flavors are available in the xsl. If not set, it defaults to a software handy default. The gdstext in this scope is the GDSII text element, the gdsnode the node element when using GDSII files. For other formats the equivalent data type should be used.

In the formats the FAB part is the name of the BB from the foundry and the args part relates to the parameter name / value for an instance of a cell. There is no principle need for BBs that have the same parameter values to use the same cell name (so using the GDS SREF or AREF) as cell rotation may give bad results. Often this is done to save some GDS space at the risk of snapping effects. Type cellname_style documentation:

cellparameter_prefix

Set the prefix for the parameter gdstext.
If not set, Parameters will be used.

cellparameter_style

Define how the GDS cell parameters should look like
There is no standard on this, so a few flavors are available in the xsl. The preferred setup is TABLE_ASSIGN which has the parameters in a single text element in the cell. The gdstext in this scope is the GDSII text element, the gdsnode the node element when using GDSII files. For other formats the equivalent data type should be used. Type cellparameter_style documentation:

cellport_style

Define how the GDS cell ports should look like
There is no standard on this, so a few flavors are available in the xsl. If not set, it defaults implicitly to FREESTYLE, which makes an deck quite complex. For platform design kits this is however a good value. Type cellport_style documentation:

polygonSize

Normally a value between 1000 and 7000; a GDS record is maximum 64kB, so the maximum is just below 8000.
If this is not set, in OptoDesigner we use 6000. Type polygonSize documentation:

wireSize

Normally a value between 1000 and 7000; a GDS record is maximum 64kB, so the maximum is just below 16000.
If this is not set, in OptoDesigner we use 6000. Type wireSize documentation: