OpenRCX Extraction Rules File - does it support multiple widths?

[chrisgelinek-rl]

Hello,

I'm generating an RCX rules file from some capTbl files from a proprietary PDK, which include multiple widths for each routing layer. Interestingly, the provided widths in the capTbl files don't match the default routing widths in the tech LEF. I'm guessing that other tools would interpolate between the provided widths to calculate the R/C values for the actual wire width.

1. Does the RCX rules format support the specification of multiple routing widths?
2. Is this supported by the RCX engine?
3. Is there an example of such a file with multiple widths I could use as a reference?
4. More generally, is there a document/spec describing the rules format?

This may also help the discussion at #6912 (comment).