Originally Posted by Quack!
This is half true.
Modern programs can read your tangents and binormals nowadays which can produced near-on synched results without handplane.
UE4, Substance Designer/Painter, Toolbag2, xNormal all can read your tangents and binormals from your .FBX file. So this means that a bake in max, should look 'synched' in all of these packages as long as you use .fbx and send/read the tangents and binormals from the file.
With that said, harsh triangulation like in your image can still produce artifacts. The most efficient way nowadays, if this asset is for the current generation, would be to throw a bit more geometry at it(like you did).
I think you explained it best.
I did export it as an FBX with the tangent information and I did Split UV's properly and smoothing groups by UV islands but UE4 and Marmoset just wasn't having those long Triangles.
Upon adding more geometry I realised I was still getting smoothing problems in some areas even with long stretched quads on flat planes. Something everyone forgot to mention is that I should "triangulate
" my mesh then Bake and export. That fixed every single issue and the normals work crystal clear now.
I don't think that would have been the case with the long triangles though as that area was already triangulated.
So correct me if I'm wrong but the conclusion is: don't use long triangles on non-plane surfaces if you don't want shading errors