What are edges?
When two surfaces meet in your SketchUp model, it creates an "edge" which appears as a bold black line in your model.
Learn more information about edges in SketchUp here.
Turning off/on edges in SketchUp
If you want to turn off or on the edges in Kubity, you must turn them off or on in SketchUp before exporting. Here's how to do that in SketchUp: