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参考：
Normals bake with ugly seams – Substance Forum
normalmap seams when I save into unity – Substance Forum
Normal map seams in Unity – Substance Forum
Normal map from painter Causing Seams in Marmoset (And vice-versa) – Substance Forum
Tangents & Shading for Normal Maps – YouTube
Perfect Normal Map Baking in Substance Designer 5 without a Handmade Averaged Cage – YouTube