[UE5.2]How to save custom texture MIPS?

[AlienRenders]

I’m generating my own texture MIPS, but I can’t seem to save them. Every time I save, it regenerates the MIPS and overwrites what I created.

I tried writing to the source mips. That doesn’t work. I then tried compressing the data to DXT1 and saving to the PlatformData’s BulkData MIPS and this does show up correctly in the texture viewer. But if I reload the editor, it’s all gone. The highest resolution does stay, but I believe that’s because it grabs the data from the source, but not any of the other mips.

I also don’t know how to limit the number of mips. I need to limit it to 7, but it keeps going to 13.

Anyone know how to save mips? This is editor only BTW.

[AlienRenders]

Been searching for this for several days and just as I post this, I found the answer.

There’s an option “Mip Gen Settings” that you can set to LeaveExistingMips.

In C++, it’s:

IOTexture->MipGenSettings = TMGS_LeaveExistingMips;

And for the number of mips, just delete the ones you don’t want:

Assuming you filled in the source mips…

  while (IOTexture->GetPlatformData()->Mips.Num() > IOTexture->Source.GetNumMips())
    IOTexture->GetPlatformData()->Mips.RemoveAt(IOTexture->Source.GetNumMips());