Hello there,

I'm assuming that you've duplicated the target geometry then adjusted the vertices on the duplicate to your satisfaction. Selected the duplicate then shift selected the target geometries and finally performed the create blendshape command.

If you've done it any other way it probably won't work (although you can create the blendshape node before moving any vertices). Access the blendshape control through Window > Animation Editors > Blendshape.

Take it easy,

Mat.