From blender to unreal smoothgroup and shading I have an issue with building a low poly model for Unreal.
There is the picture of the model in Substance Designer


The same model in Marmoset



You can see there are some weird crosses all over the model.
The same crosses are in Unreal 

The model very simple and I'll be happy to keep it simple. Here is a Blender view
 
What do you think how can I fix those issues? It is obviously because of smoothgrouping but why then it works in Substance?
You can uneversaly try to export a .obj if you only whant a mesh. In the settings you will find a addon tab that have a unreal import-export feture disable in 2.79 (.psk/.psa)

The problem is usaly that the export are missing information or is procesed diffrent and you will need to deal with it in the other program