This is a Houdini Digital Asset (HDA) to produce Tree House inside of Houdini or in other packages where Houdini Engine is available like Unreal Engine 4 or Maya. It offers a lot of parameters to tweak the style of the tree house; from the cabin itself, to the deck and also for the staircase that leads to it.
It's possible to specify a trunk mesh to get accurate support and detailed link in the interior and on the top of the roof; as well as window and door mesh to customize the cabin further.
Everything is UVed.

The video is a simple OpenGL render from Houdini.

The tree is not part of the asset and is not made by me.