The first image is a mesh accuracy error you get when you move the player too far away from 0,0,0 in world space! I circled in red, the “cracks” showing between the meshes. When the floating point values of the vertex positions get too big, they can’t accurately plot to screen space and have to “round down”, leaving gaps. The solution? All open world games have to deal with this (Skyrim, GTA, etc.) by seamlessly moving the player, and the entire world, back towards 0,0,0 as the player moves too far away. I’ve almost finished implementing a solution for that.
The 2nd image is a mock up of how I’m generating continents using “plots”, circles that contain information on what should be randomly generated within them, eg. entire biomes, and within that, forest plots, etc. It’s also a mockup of how I’ll use perlin noise to generate the continent and clip it off at a certain height to actually generate the land mass, then add mountains etc. on top of that.
The remaining pictures are of me playing with different skyboxes and adjusting my “atmosphere fog” to match what’s going on in the skybox. There are no mountain ranges in the skyboxes, those are my mountains.