"Hard edges" on a smooth mesh

The issue is simple but I have no clue as to what’s causing it, here’s how it goes.

First I’ll make a smooth shaded mesh in blender (I’m using the 2.78 version)


So in order to import it to UE4, I’ll export it to FBX, with smoothing set to face, and tangeant space enabled.
Then right click into the asset browser in the Unreal Editor, and import it with its normals and tangeant space.
So far so good. But alas, something has to be wrong, because the mesh now gets some not-so-smooth edges.

I personally do not have a single clue as to why this is happening. I’ve tried changing every parameter that I mentioned earlier (smoothing normals/face/edge ; building the normals instead of importing them…) and so far I’ve gotten the same result every time. What could I have missed ?

Hi, are you using this to smooth the mesh in blender? Smooth Modifier — Blender Manual

The deform modifier does not change the vertices of the model. From the docs: " It smooths without subdividing the mesh - the number of vertices remains the same."

Basically you need to run a smooth that actually adds vertices. Good luck because I don’t know Blender well :frowning: (this has a very easy solution in Maya!)

Ticking “Loose edges” in geometry when exporting seemingly fixed it.

“smoothing” refered to smooth shading, not the modifier or the tool.

I’m glad you found the solution, I should use blender more often!