Orbx losing reference to vdb

[overthere]

Hi,
Can anyone tell me what the best practice is for using vdb with orbx in unity?
I can get it working but intermittently the reference to the vdb seems to get lost for no apparent reason and I get an error of the form:

Invalid AssetDatabase path: F:\Unity\Octaneproject\Assets/test/orbx/test.vdb.orbx. Use path relative to the project folder.
UnityEditor.AssetDatabase:AssetPathToGUID(String)
OctaneUnity.OctaneUtility:LoadOrbx(String)
OctaneUnity.ORBXFileDragAndDrop:SceneOnGUI(SceneView)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

And in the octane log: cannot import a regular grid from an empty voxel buffer.

Seemingly identically referenced orbx's (both orbx and vdb in assets folder of unity) will still work when previously working ones no longer do.
It's a real shame as it's such a nice workflow when it is functioning.

Thanks
Andy

Win10, octane 2020.1, Unity 2019.3.6f1, 1800x, 32GB, RTX2080

[overthere]

I think I've found my error, I wasn't in fact referencing the local location for vdb's for some of my orbx that I thought I was.

Confusingly this will actually work the first time you import the orbx, but then never again after saving and reopening the project.