I have some contour lines in a geodatabase. They are z enabled. I'm using ArcGIS Pro to create a scene and then sharing that to ArcGIS Online. I'm using the default elevation layer and have used Pro to project all contour line files to Web Mercator prior to sharing. The symbology of the lines is a simple line symbol. They look great in ArcGIS Pro:
They look awful and are effectively unuseable in ArcGIS online:
So far I've tried altering the line width keeping in mind desired resolution as described in the ESRI docs here.
I've had this problem previously when exporting from ArcMap to PDF and the ESRI docs mentioned something about windows graphics and that Pro should be used instead (can't find the link now). This worked for exporting to PDF. The same is not true of exporting to ArcGIS Online.
Pro doesn't seem to have any options to choose resolution or change anything much when sharing to ArcGIS online and I thought perhaps the coordinates are being rounded? Not sure but would very much like to hear any thoughts or opinion. Geonet has yielded no results so far.
I've now tried sharing the map as a feature service from ArcMap. Viewing it in map viewer on ArcGIS Online the lines are fine. Viewing the same feature service in Scene Viewer in ArcGIS online the same problem exists.
I'd also be interested to know if anyone can replicate this problem.