Placemark for GeoJSON for Perspective Mapping?

Has anyone used Placemark or similar tools to build GeoJSON for Perspective maps?

The docs reference geojson.io for this task but that's for a use case where you can trace or pin on top of an existing map or satellite imagery layer.

My use case requires mapping polygons and placing pins on future construction sites where we have very detailed geographically accurate AutoCAD drawings but we need to convert objects on those drawings into map objects for Perspective to display.