How to load Large spherical maps as environement

How do I go about using a large 15000 pixel spherical sky image in the scene. I can’t seem to do it through BP as it limits the size of the map and cant seem to control the UV mapping on it.


You want it as cubemap or flat image? I do not think that any GAME engine supports 15k textures.
If by spherical you mean cubemap , then i cannot help you i do not know how to split cubemap into smaller textures.
For 16k x 16k you need 16 4096x4096 textures I doubt that any graphic card can load this at once.
I am also sure you do not need that 16k resolution there, optimize your goals.

I had similar problem to yours, but on mobile and 2048x2048 cubemap was too big. So i rendered it again as separate wall textures. Applied all to box with correct uv mapping.
Then i did turbosmooth on box until it became sphere. Now i have nicely uv mapped sky sphere mesh that i can apply my textures without going for cubemap.

Because my textures are not cubemap i can do much more operations with them, much cheaper.

So i suggest you make same cube, render your texture as 6 sides. Make atlas out those textures so each is not bigger than 4096x4096, apply them all to your cube turbosmoothed to sphere.
For using more than 1 texture per face, either uv map that face to have 4 submaterials. OR do material in unreal that stitches together 4 textures.