Add Raith MBMS Paths

[MatthewMckee4]

Raith MBMS paths are normal paths but store some additional data.

Base element refers to another element in the gds file.

Below is a normal gds file with 2 cells. Cell "1" has a box in it, cell "2" has a normal path in it.

This is the gds file after converting the path in cell "2" into a Raith MBMS path referencing cell "1".

The cut off data is:
RaithPXXData: 0 0 0 0 0 0 0 0 0 bd ff 40 0 0 0 0 0 6a d8 40 0 0 0 0 0 0 f0 3f 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0

This raith pxx data is structured the following way:

The path in cell 2 now has the following attributes:

Please let me know if you are able to do this or if you need any more information from me. Thanks

[heitzmann]

@MatthewMckee4 I have no time available to implement such a feature in the foreseeable future, sorry.

[tvt173]

hi @MatthewMckee4, you should be able to do this with gdsfactory version 8

import gdsfactory as gf

@gf.cell
def my_path() -> gf.Component:
    c = gf.Component()
    # add your path here
    c._kdb_cell.add_meta_info(gf.kdb.LayoutMetaInfo("RaithPXXData", "Your Data", persisted=True))
    return c

if __name__ == "__main__":
    c = my_path()
    c.show()

this new major version of gdsfactory should be released within a few days, but you can try it now by pulling and installing from the main branch on github. if this functionality is critical to you, i suggest you give it a try!

@sebastian-goeldi

[sebastian-goeldi]

Yes, this is possible. But if it should be restored on read, c.info["my_info"] is thebetter way. This gets serialized and deserialized.other metainfos than settings/infos/ports are currently ignored by kfactory and consequently gdsfactory (on load).

Also, I belive the initial example is in user properties. I believe gdstk can also write those?

[tvt173]

@sebastian-goeldi , I was going to suggest that at first, but in that case it seems like the attribute name gets prefixed by kfactory:... and I was assuming that the application here needs the attribute exactly named to be processed by the tool correctly. there's no way to avoid the prefix when saving into the info, right?

[sebastian-goeldi]

Ah, I see. No I don't think so. So if this matters, I think the MetaInfo is the wrong place then, assuming these are user infos.

The thing is the metainfos are not a gds standard but rather a KLayout addition. So if it's an external tool, it would be important to know the target format. If it's gds it becomes tricky as user properties only can have a dict[int, str] format. Oasis can do dict[str|int,Any] format. Ofc shouls the external too support meta infos (probably not as it's a rather new additon for KLayout), then if prefix matters, your way works of course.

[Rory-Lambert]

Hi guys, colleague of @MatthewMckee4 here. I run the Raith tool which requires these unusual paths. The file type required by the machine is .gds. As far as I understand from our discussions with the tool manufacturer, the Pxx data is simply appended to the end of a normal Path instance. This certainly breaks the normal GDSII specification, and caused files generated by this tool to fail to open in Klayout. We managed to convince the developer of LayoutEditor to implement these structures for us. Firstly, to handle file I/O such that any of these custom paths were just handled as normal paths, rather than crashing the editor. Then, eventually we gained the ability to add, remove and edit the metadata, including via scripting. I want to do the same thing here with the GDStk/ GDSfactory toolchain. I think from Matthew's example provided above, they are defined as their own record type ('MBMPath') and the metadata stored in the RaithPxxdata attribute of this record. I've made an example GDS file which I will attach here, perhaps it's helpful? Note that I had to append the .txt suffix to workaround GitHub's limits on file types that can be uploaded. mbms_demo.gds.txt. Below I also paste the output of our rudimentary GDSII record reader, in case its any use.

If you guys (or @MatthewMckee4) can generate a file that you think might work, I can very quickly throw it in the Raith software and see if it behaves as expected.
Many, many thanks all!

HEADER: 3
BGNLIB: 2024 6 4 10 6 47 2024 6 4 10 6 47
LIBNAM:mbms_demo.gds
UNITS: 0.0001 1e-10
BGNSTR: 2024 6 4 10 3 36 2024 6 4 10 3 36
STRNAM:this_is_the_base_cell
BONDRY:
LAYER: 1
DTATYP: 1000
XY: -5000 -5000 5000 -5000 5000 5000 -5000 5000 -5000 -5000
ENDEL:
ENDSTR:
BGNSTR: 2024 6 4 10 5 4 2024 6 4 10 5 4
STRNAM:this_cell_contains_an_MBMS_path
RaithMBMPath:
LAYER: 2
DTATYP: 1000
WIDTH: 60000
XY: 0 0 0 1000000
SNAME:this_is_the_base_cell
RaithPXXData: 0 0 0 0 0 0 0 0 0 4c dd 40 0 0 0 0 0 6a e8 40 0 0 0 0 0 0 f0 3f 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0
ENDEL:
ENDSTR:
BGNSTR: 2024 6 4 10 6 47 2024 6 4 10 6 47
STRNAM:this_is_what_the_tool_woul_write
AREF:
SNAME:this_is_the_base_cell
STRANS: 0
COLROW: 2 33
XY: 0 0 100000 0 0 990000
ENDEL:
ENDSTR:
ENDLIB:

[tvt173]

IMHO that's a pretty bad limitation... what about trying to convince the vendor to do it in a compatible way that will open in Klayout (and other tools)? you can try the output of the sample script i put above. note that for demonstration purposes, it only has the attribute with "Your Data" as the data value, and no actual paths or shapes. and i send as a *.gds.gz because github will not let me send a *.gds, but you should be able to open in klayout as-is or decompress to use otherwise
raith_attributes.gds.gz

[Rory-Lambert]

IMHO that's a pretty bad limitation... what about trying to convince the vendor to do it in a compatible way that will open in Klayout (and other tools)?

Yes mate, its an awful limitation! It my biggest headache with this machine by far, and it's been really difficult to do proper scripted GDSII layouts while working around this issue. Its one of the biggest reasons we are pushing to get this implemented in these packages. I have spoken with the tool vendor at length, and it was difficult enough to get them to share enough about their file structure so as we could get this far. I don't think its possible that they will make a change to it at this point unfortunately.

you can try the output of the sample script i put above.

I think that your script adds meta data to the cell? I don't believe that this would be appropriate - one cell can have many MBMS paths, each of which containing its own metadata, so as I understood it the challenge is to pack these properly into the GDS record.

it only has the attribute with "Your Data" as the data value

Apologies, I don't use KLayout often, where can I find this info?

[tvt173]

you can view the info in klayout like this:

you should also be able to see the attributes in the binary of the file (i.e. if you open it in notepad)

to implement the functionality in a way that is not compatible with klayout is a tall order... the new version of gdsfactory is based on klayout. i think you would need to make a PR to klayout for such a request.

but personally, i think this is bad design on the part of the vendor. there are other, more compatible ways of annotating this data. I would push them towards a better solution