How to import Cube Textures from external texture file

Everytime I tried to import .dds file , it always convert to standard non-cube texture .
And I can not find any option to change the Texture type to “Cube”

Checking the default Skybox cube texture, the editor does not show anything on texture type

I’ve checked the documentation but it only says about supporting .dds file only.
Please tell me how to import texture as CubeTexture, or it this a limitation of current Flax 1.6 ??

I had success importing a skybox after making the DDS file using the nvidia texture tools we can select there the format to be a cube texture, the exported DDS was imported correctly in flax, maybe you can give it a try?


Thanks, I will try and give an update

I tried the NVIDIA tools you mentioned, and it works.
Although there are still a few problems :

  • The Tools need a special format of Texture to convert to Cube Texture which requires us to convert
    Equilateral texture (e.g : textures in PolyHaven) into Long strip of textures using this tool
    GitHub - matheowis/HDRI-to-CubeMap: Image converter from spherical map to cubemap
    → so my suggestion is, it will be better if Flax Engine can support importing CubeTexture without having to do these hassle

  • The imported CubeTexture does not seem to have “Radiance Convolution” mip filtered textures in it.
    For people unfamiliar with this term, in Unity and Unreal the imported CubeTexture has 6 blurred images, which is stored inside Mip channels. Then this textures will be rendered accrodingly to the Object’s roughness (smoother material shows clearer image like mirror, while rougher object will have more blurred reflection)

I will create a different post, regarding this issue because the topic is irrelevant to this post

Yes I agree that cube texture should be handled at the import directly from the engine of course and I noticed also that we have almost no control on the mipmap generation of the texture (unlike UNITY), for example some textures do not look good to be mimap(ed) to the extreme and should only have 2 or 3 levels of mipmaps (specially when you have alpha), I saw also that for anisotropic filtering we have to use texture group and it is at the shader level that we set the function, maybe the “Radiance Convolution” mipmap feature you are referencing to is also part of the shader or could be done into the shader?

Radiance convolution is actually an algorithm to “Blur CubeMap correctly accroding to its roughness” based on BRDF function, so it’s not just applying a Gaussian Blur randomly for example.
However in practice, the algorithm is so slow and not suitable for realtime rendering.
If you’re interested here is a paper about the algorithm written by Brian Karis of Unreal

So to compensate the high-cost of computing this convolution in realtime, the most common technique is to pre-calculate the convolution (blurred) texture and store them inside MipMap filter.
Then using the texture, we can sample it manually or automatically done
by engine to apply how blurred the CubeMap to our desired object.
So it is not ideal for us to compute the convolution inside shader (although we could),
because it will take too much of performance (except if you want to create a still rendered image)

In Unity usually this convolution texture is automatically computed when importing the texture

Here is the import setting in Unreal

If you want to expand this topic, can you please post it in my other post ?
Because it’s kind of irrelevant since this post is just about “Asking how to import CubeTexture”