*If imported to iClone, realtime occlusion and frustum culling tool would/should need to be applied but could be limited to scene/chunk size in the beginning.

Rendering is too heavy on iClone resources if users are forced to see a vast landscape in the viewport at the same time unless you can set the viewport quality options to increments of halves, 3rds etc more like Adobe Premiere has or completely disable it with the words "rendering" in it place. Maybe you just need one more option in the Viewport shader setting ie; High, medium, quick mode, minimal, custom but now add "Off" to the list, to disable all toolbars, tabs and disable the viewport until rendering is finished. This could be full performance mode setting on the Native rendering tab, if enabled, it saves as an undo step and after rendering, it will undo that save step.

*Live link - character's and scene could be sent to World Creator and vice versa. Buildings and roads in iClone, could be marked to automatically sculpt/bool/carve the landscape sending content to World creator or the landscape auto adjusted in iClone when receiving terrain.

World Creator is a professional tool and has been used to create Cinematic Quality Films. Current tools in the market place add extra strain on iClone when several landscapes are overlapped to make it more interesting.

*Physics - I've seen solutions for landscapes that don't require the entire landscape to have a collider generated and in most cases why collisions fail is due to lack of collider/mesh resolution, self mesh would be extremely bad on performance and still may not have enough resolution for small objects.

Solution: Use a system like GI that you can place in the scene and spreads out over mesh faces - you don't need to analyze an entire mesh, you would just need dynamic colliders that match the shape of the faces within a zone of influence. This zone area is like the GI anchor which could be attached to moving objects but dynamic realtime collider shape blocks rigid and soft bodies (similar to the very first video game - pong)

With this concept, only an area effected by moving rigid bodies or soft cloth is covered/activated like a shadow being created in the trajectory.

So this post is just an idea but would attract many users, likely new World Creator users. Reallusion wants to attract elite users, this would help.

I could right now, create a large world, import it as chunks into iClone, set the chunk areas with LODs as their own Collection and manually edit the visibility state of the chunks in the timeline depending if a particular chunk was in the camera shot - this would take a very long time to setup but a world creator import plugin could be developed to automate adding chunks to its own collection, and a realtime occlusion + frustum tool could GPU Isolate only what is visible and record that on the timeline so the entire landscape would be optimized for Rendering within iClone or be optimized for rendering elsewhere.

Lastly iClone and CC4 Thread priority in my opinion should be set to high by default every time the programs are open. There is more stability and faster operations such as rendering. Most music production programs have this option yet I've never had crashes as much has I've had with iClone and CC4. It made a huge difference when I upgraded from 32 GB of host ram to 128 GB and before I was running a 4Ghz Quad core CPU, now I'm running 16 cores, 32 threads - iClone/CC4 crashes less but it tells me there is lack of realtime optimization and is why game engines are becoming the leaders in VFX/film making. These are the only bottlenecks I see limiting iClone/CC4 from being a tool that can allow customers to create and render dense scenes with ease.