Old Castle in The Mountain

The is a complex scene for Houdini procedural modeling practice. All aspects use Houdini. I use texture map from megascan assets. I use l-system to create a pine tree tool to generate a lot of different branches and trees with viriation. Using terrain tool in Houdini and create a procedural building tool to generate castle with different shape. Render in Mantra and composite in Nuke. I want to import it to unreal after I finish it. I can export the terran data into ue4 and scatter different plants on it.