Blender Octane World Creator Houdini, color grading in Davinci
I start by sculpting some basic shapes in wc add some filters on top then move on to texturing. The secret to texturing in wc is to export masks where the grass texture or rock is distributed instead of exporting the color, normals etc…
Then use the masks to recreate the material in blender that way you can scale the grass\rock texture up much higher then if you simply exported a baked down 8k color map from wc. This tripped me up for a long time constantly getting worse quality in blender compared to the viewport in wc.
The clouds are generated in houdini with 1 node yes not kidding. The free version you can export vdb no problem 