Hi,
After some extensive testing, I'm finding that normals in the substance graph in Unity are flipped in comparison to an exported texture from Substance Designer.
The attached "SubstanceGraph" image shows the settings of the graph in Substance Designer. Notice that the viewport is set to OpenGL, the Normal node is set to OpenGL, and output node is set to NormalXYZRight (OpenGL according to Substance Painter docs). Also based on the reflections, you can note that the light source in the viewport is illuminating from above and towards the camera.
The "NormalsFromGraph" image shows how the normals look when mapped to a quad in Unity HDRP with lighting coming from the same direction as the Substance Designer viewport. Note how the normals' Y is flipped to be like DirectX Normals. This is not the same as in Substance Designer. In Unity, the SBSAR has purple at the top, whereas SD shows it as cyan at the top.
If in Substance Designer, I don't export a SBSAR but instead export a texture straight from the 2D view of the output node, import that into Unity and apply Normal Map import settings, notice in the "NormalsFromTexture" image how the normals appear correctly in the OpenGL format. In Unity it is also correctly cyan at top.
The normals are somehow getting flipped from OpenGL to DirectX in the SBSAR, but not when exporting as a texture. This is with Unity 2019.3.4, HDRP 7.2.1, and Substance 2.4.4.
This problem is the same for all "usages" set in the output - NormalXYZLeft, NormalXYZRight, SNorm, sRGB, etc. exported from SD and imported into Unity.
However, if NO usage is set for the output, then when importing that substance into Unity, the texture appears correctly with cyan at top, BUT it doesn't function correctly with lighting as a normal map because it is not detected as a normal map by the substance engine. We also can't set the import settings for the texture to be a normal map because THERE ARE NO such settings in the inspector for that texture, only "Wrap Mode", "Filter Mode", and "Aniso Level". Please look into this bug.
As an aside, it would be nice to have all of Unity's texture import settings available rather than having the Navigation section in the inspector, if there has to be a choice between the two.
