my current work around idea for characters is to export the in-game mesh with a different UV tile set than one used for painting in substance painter.
so yeah it would be pretty cool if you could maybe tickbox specify if the V tile order goes up or down,
then I wouldn’t have to make any weird changes from other art authoring programs
even if I use unreal with DX12 on for ray tracing, the the udim tiles still need shuffling around to sit in the correct spots.
other than that the udims work pretty nicely if the shaders are kept simple