GDSII geometry entities such as boundaries and paths are tagged with two attributes: a layer and a datatype. The original GDSII specification allowed these attributes to range from 0-63, but later implementations of GDSII support layer/datatype attributes from 0-8191.
When merging GDSII files, the user can specify which layer/datatypes will be passed to the output file from each of the merged files.
The list looks like the following:
where the first number is the layer attribute, followed by a colon (:), followed by the datatype attribute. The comma acts as a delimiter.
When "overlaying" two similar files for comparison purposes, one might want also shift the layers from one of the files so that a GDSII viewer can separate them out. This is accomplished by providing a list for the output file.
File A and File B have data of interest on layers 3:0,6:0,6:1,15:0,17:0,17:1. In order to visualize any changes made we want to shift (in the output) the layers in File B by 100. That will make it easy to compare layer by layer.
Then our overlay program would have two separate entries:
It is necessary that an input and output layer list have the same number of elements. So even if you want to shift just a single layer, you need to specify all layers/datatype pairs in the output layer box.
Suppose we just want to shift layer 6 to 106 in File B. We still have to match the other layers.
|Download | Revision History | Price|