After using the LineCloser to close 3D lines I discovered that some vertices in my dataset were changed. My assumption was that the LineCloser only adds a segment between the last vertice and the first vertice of the polyline but the Z from the last vertice was changed to the Z of the first vertice... Changing the parameter Connect Z Mode from "First Wins" to "Ignore" solved my problem. But I wondered if the setting "First Wins" was set as Default intentionally, and if so, why?
The image:
1. The open line.
2. The closed line with the setting First Wins. The Z value of the last vertice is changed to the Z of the first vertice.
3. The closed line with the setting Ignore. Now only a segment between the last and the first vertice was added, no vertices changed.
FME Desktop 2017.1.2 and 2018.0.0.2.
Workspace attached.