This thread it really useful.
Thanks to it, I finally tried out the Freeworld 3D program.
It looks very nice and easy to use.

- Does anyone have any tips for creating terrain with it that can go into 3DGS well. Like the best formats to export to, or guidelines on how they should construct their terrain (max highmap size or whatever)?

Sorry if I sound pretty new to it. I've not messed around with the program before.
Thanks