pdaOPSlayerTrench

Tgt=Trench | (Clad & ! Core)
Define a trench operation; Tgt=Trench | (Clad - Core).
The operation is called "trench" as it is often used for waveguide trench definitions, where you draw the "core" but need to get the "trench" in GDS output. Widening the "core" to "clad" and invert will give you the "trench". This is simple to do with the xsection definition and using multiple maps. The boolean operation that combines the output is then this trenching operation.

     <xsection name="wg">
      <grid>
       <map>core</map>
       <mag widen="5">clad</map>
      </grid>
     </xsection>
    
You can use it for other operations where you need a: "direct write" or (A - B).
You can use the elements doc and tex to document the operation. This is often useful for later changes as the logic behind complex chains of operations is often not easy to follow by colleques and/or partners.
Attributes:

Structure

The attributes and 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.

<pdaOPSlayerTrench  
Clad="..."  Core="..."  Trench="..." ... > ...
  <doc> ... </doc>   list
  <groupRef> ... </groupRef>   list
  <tex> ... </tex>   list
</pdaOPSlayerTrench>

XSD

The schema file can be downloaded or viewed at xPDK_Layout.

Details

Clad

Type pdaGDSlayerReference documentation:

Core

Type pdaGDSlayerReference documentation:

Trench

Type pdaGDSlayerReference documentation:

doc

Type pdaDocumentation documentation:
This field allows some (short, few lines) documentation to be written. It can be a long string, but the idea is not to replace a design manual.
This fields is like tex which allows documentation in LaTex format; doc is restricted to plain text.

groupRef

Type pdaIdentifier documentation:
Identifiers are used in the Python library for the getName() and setName() function and can thus be used to identify the different elements in list s.
In text the specification is a letter, followed by letters, numbers, underscore or dot. The XSD schema validation is a regular expression: [A-Za-z]([A-Za-z0-9_])*

tex

Type pdaTexDocumentation documentation: doc , but tex can be a long text in LaTex format to document the layer in more detail if needed.

You can document anything relevant for the topic you want to define.

Multiple paragraphs is fine. Format is Latex, so more complex content is possible.