For sort of  background LODs where evrything baked in together .   With trees , grass covered  crumbled cityscapes ,   rendered clouds .  
Through last 20 years I  used Vue,  then Terragen, then  ClarisseFX  , then just Blender with Octane .
The first two were non stop pain in your..... Clarisse was perfect  with lots of procedural  tools . Best scatter tools I ever experienced  . Nice immediate preview . Pretty adequate  vs  VUE and Terragen  where you got nothing  especially  close  to what you saw in preview render.    Clarisse is only soft I know that could import a huge  900mil  poly alembic  from reality capture and bake proper textures from it. All at once.    Well, before they got their own baker.  
  Only one huge drawback .  It took ages for a final render.
So once Octane started to take less time for first pixels on screen and got  its  awfully, terribly inconvenient  scatter on surface  but  as a huge plus providing  instant  visual feadback for your tweaks in the render  I have gradually  moved on from Clarisse.   My guess everyone did the same  and thus she died. 
      
  Still it's not even close to Clarisse conveniences in tools . Texture baker  is way behind Clarisse  and so on and on.
So I wonder  what's other alternatives?    
 
            
Replies
it is still houdini underneath though so you have to be prepared to stab yourself in the eyeballs if you want to do anything complicated
I just remembered katana exists. might be worth a look