Skysphere from panoramic image

Development Rendering
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I want to take a panoramic image and make it into a skysphere, particularly the public domain image here:

4096×2048 4.44 MB

[Galaxy Panorama][2]

Applying this to a regular sphere gets pretty close to what I want, but I need it “inverted”. Applying it to the skysphere in UE4 produces an undesired mirrored effect described here: https://answers.unrealengine.com/questions/215809/attach-texture-to-my-skybox-without-mirrored.html

Does UE4 have an “inverted” sphere that such a panoramic image could be applied to for an “instant skybox”? It seems this would be a much easier way to get a realistic skybox from an actual panoramic image. The existing way is hard to follow, trying to do it in gimp, and not having paid tools as described in the tutorials. Is an “inverted sphere” a valid / easy way to make a sky sphere?

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I finally figured it out:

  1. You can create a sphere in Blender (which is free) and invert the normals. Delete the square, add an ico sphere, put subdivisions to 5, tool - shading - smooth, scale to 15000 x, 15000 y, 15000 z. At the bottom, switch to edit mode, then select mesh, normals, flip normals. Change mode at the top to UV Editing mode. Click Shading and UV’s tab (in the middle), Unwrap, Sphere Projection. Save your file, and export as FBX. I want to try to make this free on the marketplace, but apparently that isn’t feasible. I have made it available here for free:
    Simple Sky Sphere

  2. Import the .fbx mesh and image into Unreal Engine.

  3. If you want something other than a realistic starry sky, try to find a panoramic image that you are allowed to use.
    The one I found is public domain, available here: File:Tycho catalog skymap v2.0 (threshold magnitude 5.0, low-res).png - Wikimedia Commons

  4. Make a material with the image, set it to no lighting, and plug the texture into the emissive field. You may want to multiply the output by a const 3 vector, and set it to dark grey to tone down the brigthness, save.

  5. Optionally, you can make the material translucent, and plug the color node of the skysphere texture into the Opacity tab as well. This will make the skysphere see through except for the stars, and let you put it in front of the regular UE 4 skysphere as well. This would allow you to take advantage of the regular skysphere effects, while having an amazing starry background as well.

  6. Place your sky sphere mesh, and apply your material to it. Hopefully you will now have a beautiful sky box! Please reply if you have any questions!

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Hey! Your sphere is what I’ve been looking for!! Great stuff!
Unfortunately when I use your sphere in Unreal Engine 5.2.1 my panoramic textures appear to be rotated and rotating the sphere manually is near impossible.
I’ve tried importing the FBX in different ways and with the default settings with no luck.
If I apply any of my panoramic textures to the regular sphere they appear as they should, without any rotation but the poles look terrible and those look great whenever I use your sphere.
Is there a way to fix this?
Thanks in advance!