I love the glTF writer and we have been using it a lot in conjunction with our Cesium based applications to help bring customer data into their interactive 3DCityModels.
glTF is awesome because it supports both vector (lines/points) and True 3D surfaces. One issue we're running into, however, is that I'm unable to style the vector features in the output. The fme_color attribute appears to be ignored and the GeometryColorSetter/AppearanceSetter rejects it because it is InvalidGeometry...This means we're unable to bring in colors from CAD drawings which makes it lose some of its value
I would love if the gltf Writer would recognise the fme_color attributes.