New GDA2020 Geocoordinate Systems in CE - how does it work?

Mark,

In order to migrate from GDA94 to GDA2020 you must first change or correct the Geographic Coordinate System from the GDA94 system, to the equivalent based on GDA94/GSB -- without reprojecting. This is a Correction from a coordinate system that used to be based on WGS84 to something that is not anymore (GDA94 used to be considered coincident to WGS84. Now it is GDA2020 that is considered coincident to WGS84 but we cannot change the definition of GDA94 after its existence).

Once that is done you can reproject to the GDA2020-based Geographic Coordinate System.

So your process will be a two-step process; 1. Correct the Geographic Coordinate System, do not reproject the data.  2. Reproject the data

Hi Dan Weston
I had to reproject a model from GDA94 to GDA2020 and your approach seemed to work, however since then, my reference display has been problematic. All references appear to be linked correctly and they do display in the 3D view, however nothing is showing in the default view. 
I have noticed that the X- and Y-offset of the references now shows a value of "-nan(ind)". 
Have you by any chance experienced the same issue or have any suggestions on how we can resolve this?
Regards, 

Hi Dan Weston
I had to reproject a model from GDA94 to GDA2020 and your approach seemed to work, however since then, my reference display has been problematic. All references appear to be linked correctly and they do display in the 3D view, however nothing is showing in the default view. 
I have noticed that the X- and Y-offset of the references now shows a value of "-nan(ind)". 
Have you by any chance experienced the same issue or have any suggestions on how we can resolve this?
Regards, 

Hi Marise,

We have just started experienced this and it seems to be due to references not using a "Geographic - Reprojected" orientation. After reprojecting a DGN, the next time we open it all the references change to -nan(ind). I then have to change all their orientations to something else like "Coincident "and then back again and they are fine from there on.

Very frustrating because this will naturally be an issue for DWGs and other references that dont use the concept of a GCS, as well as generic DGNs we dont have this set. Plus the fact it does not exhibit till after you reopen the file makes it easy to miss.