Normal problem when using Morph Target


I’m trying to use morph target, to morph an hexagon into a cube. The problem is the resulting normal.
In blender each vertex has 1 normal / face and I exported using Face smoothing group.
I want to keep the hard edge, i tried many way to import but it’s never the way I supposed it should be.

when importing the mesh:
if I import normal from mesh, the normal are ok, the mesh looks not smooth, but when changing the weight, the normal are not updated or in a bad way. And the edge in the middle of the cube is visible.

if I use the unreal normal computation I loose the hard edge, and have some back artifact.

I spent so many hours trying to figure what’s going on…

the mesh i’m using: at master · Hekiat/ · GitHub

thank you very much for any idea or response :slight_smile:



So after hours of research I figured out.
That it’s a known bug that won’t be fixed:

for more details i found this thread:
or here:モーフィンク時にモーフターケットの法線か適応されない.html#answer-463657

So if you want to have this kind of sharp edge you will need to change your geometry.

I hope it can help.