Many objects, such as triggers and paths, are built from vertexes – for example basic trigger has four of them. You can edit those, creating non standard shaped objects, using Vertex Edit tool. To access this edition mode select object you wish to edit, change tab in main editor window from “Scene” to “Tools”, and choose “Vertex Edit” tool.
Adding and removing vertexes is performed by holding ALT and clicking LMB in place you want to add or remove vertex.
If we’re editing a path, we can easily add new vertexes on the end of path by CTRL+LMB
You can edit and add new vertexes (corners) to selected areas.