I am using the Lands to Revit pipeline via RiR - I am using Revit 2025.4 and have the latest versions of RiR and Lands loaded. When initiating the Lands pipeline in Grasshopper to send a Lands terrain to Revit, I have the following error message after double clicking the terrain in the LandsAll pipeline button-
I think this is related to a recent change in the latest version of Rhino.Inside Revit. This bug has been reported to the developers of RiR, and they are investigating how to solve this issue. You can try to revert to a previous RiR version (June-July) in order to use Lands in RiR.