Rhino Landscape & 2nd UV channel to Unreal?

Hi all,

As a long time Rhino & 3DS Max users, I recently got into Unreal for creating real-time Arch Viz content - but I am struggling to get accurate landscape mesh/data into Unreal from Rhino. I can import the Rhino landscape as a simple mesh, but then I could not use the grass tool on it; I can create a height map from Rhino and create a landscape in Unreal, but then the world location and the scale would be inaccurate. I am wondering if anyone has a solution to this?

For light map creation, I have been importing my Rhino models into 3DS Max and using Steamroller to unwrap to 2nd UV channel - the exporting and importing time adds up a lot in the long run. I am wondering whether there is a way to create a 2nd UV channel in Rhino?

Any advice and comments appreciated. Thank you.