How can I convert a sketchup lod4 building model in cityGML format

Hi @kajal​ - Welcome to the FME Community! What have you tried so far?

There's an informative webinar from quite a while ago that I hope is still applicable: How to Easily Read and Write CityGML Data (check out the section on Writing CityGML at approx. the 34 minute mark followed by a Sketchup to CITYGML demo). There's also a link on the page to download the demo FME workspaces!

Some other references that might help along the way:

• SketchUp Reader
• Writing CityGML with FME
• CityGML Writer

This should hopefully get you started!