Dear Frank,
Thank you for the question and I am sorry for the issue!
Unfortunately, the native Skylight tool from Archicad is not yet available as separate component in Grasshopper. I entered it as a wish in our Wish List database (please refer to it as #12871). Hopefully our Product Management team will consider implementing it in the future!
Thank you for your understanding, and I am very sorry for the inconvenience!
Have a great day!
Best regards,
Minh
Minh Nguyen
Technical Support Engineer
GRAPHISOFT