Volumetric Clouds - Problems with World Origin Rebasing

Development Rendering
, , ,
1

Hi, hope you can help me:

We are using World Origin Rebasing (from World Composition) for our game world in unreal engine 4.26. While this works very well with every system so far, the origin rebase causes problems for the volumetric clouds. At every rebase, the clouds are shiftet in an instant because they use the “Absolute World Position”-Node in their material, which does not respect the shifted world origin.

We tried adding the world origin offset (obtained from a “applyWorldOffset()”-function in an AActor) via material parameter to the absolute world position in the material, but it did not work as intended (and the shifts still happen).

So my question is: Is it possible to use the volumetric clouds with world origin rebasing in unreal engine 4.26? And if not: Is this feature supported in Unreal Engine 4.27 or 5?

Thank you for your time!

2

Yes that is possible. You need to subtract the object position from the world coordinates. Also for some strange reason when frist entering the scene no other objects are allowed to be render or the clouds have be turned off first until everything is loaed or the the clouds may follow your rebasing. I don’t know why that happens.

This project uses world rebasing with clouds being fixed in space: Alexander Kenkenberg / Real-time Volumetric Cloud Visualization of Meteorological Simulation Data · GitLab
Maybe it will help you.

Also concider if you arre in UE5 with the new large world corrdinates you may not need to use world origin rebasing anymore and should be fine even when populating an entire earth.

1 Like