Renderotica

It would probably be better to use displacement for the larger veins and normal map for the smaller detailed veins.

Did you try to invert the red channel?

I've tried every which way (swap R, swap G, swap R and G, tangent Space, world space, etc).  I think it's just how normal mapping works in Unreal Engine.  I added some parts to the shader to dial down the intensity of the map but still, from one angle (left) it looks fine but from the other (right) the relief looks like indentation.  It's dependent upon the angle between the light, the object and the eye.  Displaying normals in Maya everything looks alright too...  

 

I think the probability of me getting it to work with OpenGL is close to zero. DX11, DX12 and Vulkan are the only options in the standard build.  I don't fancy derping around in Github to work out how to do it (that's my day job).

 

Edit: Derp.  Misread this.  The difference between GL and D3D is flipping the green channel.  I've done that in Unreal to no effect (it flips the direction of the problem but the problem still exists).

Edited by user Saturday, December 21, 2019 9:14:50 AM(UTC)  | Reason: Not specified

I think I've nailed it.  It was definitely strange behaviour with tangent/binormal export.  For anyone who comes here looking for how to do it, three things to note:

(1) The green channel should be flipped in the map's properties.  
(2) Maya should be set to Z-up (in settings) and the FBX exported with Z up.
(3) Send normal map through DeriveTangentBasis block in the shader graph if using UV1.

For 2, once you change settings to Z-up, the mesh and skeleton should appear to be lying down.  Just do this for the export.  For 3, Unreal Engine's shader system generates the tangents and binormals for UV0 (channel 0).  Channel 0 is what I'm using for the base mesh.  I copied the futa UVs to UV1 in Maya.  UV1 is the channel on which we need the normal map.

Maybe there's still something I'm not doing right that would fix all of these problems with a mouse click but for now it's working and looks great.  

Sorry for late reply. I haven't checked forum for a while. I used LayLo 3D's Genesis 3 to Maya plugin to export the base mesh. The base mesh "welds" or joins the geograft and you delete the exported shell in Maya. The next step is to add a second set of UV to the mesh in Maya. There's no export of morphs for the gens though (this is a limitation on the Daz side, not Laylo's script). If you want the morphs you have to make them yourself.

I'm pretty sure all this is also possible in Blender, though I do not have the workflow for that.