Since you are adding it to viewer.entities, you need to remove it from there as well. Either viewer.entities.remove(redLine) or viewer.entities.removeAll() will work. Try pasting this code into Sandcastle:
var viewer = new Cesium.Viewer(‘cesiumContainer’);
var redLine = viewer.entities.add({
name : ‘Red line on the surface’,
polyline : {
positions : Cesium.Cartesian3.fromDegreesArray([-75, 35,
-125, 35]),
width : 5,
material : Cesium.Color.RED
}
});
Sandcastle.addToolbarButton(‘Remove’, function() {
viewer.entities.remove(redLine);
});
Sandcastle.addToolbarButton(‘Remove all’, function() {
viewer.entities.removeAll();
});
If you have an example that you think should work but doesn’t, please let us know.