Hi everyone, I want to make a space sky, i. e. you can see background textures into all six directions. It seems that there are two major methods, that I want to call “Spacebox” and “Spacesphere”. I have several questions to both of them.
Is described in the wiki tutorial “Skybox from DDS cubemap”. I am wondering if this method may be inefficient.
- Importing the DDS file to UE takes a long time, e. g. about 20 minutes for a 6 x 4096x4096 dds texture file. Is that normal, how can I make it faster?
- When opening the texture after importing it, it looks like a single rectangular texture with very distorted poles. Does that mean that these poles use a lot of memory although they cover only a small area on the skysphere? And do they use this much memory after mapped to the sphere, too?
- The surrounding sphere probably consists of hundreds or thousands of polygons (spaceboxes only use six), and the dds file has to be mapped to these polygons. Isn’t this all very expensive, especially when compared to the other method (see below)?
I created a cube in my favourite 3D modelling tool and unwrapped it to a 3x2 grid, see:
When I now export my skybox as six single images and merge them to one big 12288x8192 image (i. e. a 3x2 grid each with size 4096x4096), this seems to be a perfect solution. (The rest of the steps to be done is analogous to the other method.)
Nevertheless, there are some issues:
- When opening the texture, UE says “Attempting to import 12,288 x 8,192 texture, proceed? Largest supported texture size: 8,192 x 8,192”. Though, it seems to work. So, is this a problem?
- The texture is not quadratic and its lengths are not both powers of 2. Does this yield in a waste of resources, e. g. by automatically padding the texture?
And, of course, my most important question is: Which of these two methods should be prefered, and why? The spacebox method seems to be easier and save resources, but the only satisfying tutorial in the UE wiki prefers the spacesphere method.
Thanks a lot for reading my concerns, hoping for answers,