I want to map my normals to each polygon vertex by using eByPolygonVertex and eIndexToDirect, but I found when I import the genereated .fbx file into Maya,the normals on the vertices are not what I assgined to them, instead, those normals look like generated by Maya automatically.I don’t think there’s anything wrong with my code because I used the same way for UVs and they act very correctly.

Then I reorganized my data and did a test using eByControlPoint and eDirect mode, this time I see the correct normals on the vertices.

Can we only do this using eByControlPoint? It seems like the samples I checked are all using this mode for normals. But this won’t fit my needs because I could have multiply normals on one control point.

Any help I’d really appreciate it.

You can duplicate the vertices for the all faces that needs to have their own normal.