I am struggling with an issue when exporting to substance painter.
whenever I export my model into substance and bake it, all the world space normals have discontinued UV seams, this means triplanar projection and smart materials all have seams as well.
I have been trying various methods to find out how to get around this but each time the seams are clearly visible and are affecting the way substance painter smart materials apply to the model with harsh seams and bad mapping.
I will try and cover what I have tried thus far.
I have tried high to low poly baking, cages, edge split modifier, triangulating before export, normal smoothing 180, clearing all edge sharpness or adding edge sharp to UV borders and re-working UV map multiple times.
Some of these has changed the bake slightly but not gotten rid of the seams. from what I have read on various forums it has something to do with smoothing groups and UV seams but I have not yet seen a good solution.
I have included bellow a test piece that shows the issue in a png and includes a blend file and FBX export.
any help would be much appreciated as this is really putting a block in my asset workflow.
The only thing I can add is that if I use "smart UV project" in blender it solves the issue, but this means I can't set my own UV cuts/islands and i have to rely on what the blender script spits out which I don't like for neat UVs
Please note the test piece is a small piece of a much bigger mesh so the unwrap is small but as it should be and will be baked at 4k.