That bend is probably going to have some issues on the base Genesis 8 no matter what you do, but from the image it look like you’re putting the whole bend on the shoulder. It needs to be split between the collar and the shoulder. The image below is with JCMs for the collar and shoulder as well (connected via my plugin https://www.unrealengine.com/marketp…/daz-to-unreal). You might also need to play with the shadow settings on the character a bit.
The seems you’re talking about might be in the texture. A lot of the Daz Marketplace assets have textures that cut off right at the edge of the UVs. So when lower mips get used, a white or black line will get merged in at the edges. That’s why they appear and disappear at certain distances and angles. The normal maps in particular can make a weird edge in the lighting. I think the fix is to go paint in a little extra in the textures.
