If you are not satisfied with the source interpolation result, you can set the keyframes manually. However, you will have to set the keyframes throughout the clip—you cannot use source interpolation in conjunction with manual keyframes.

To set a keyframe manually:

1. Go to the frame corresponding to the keyframe you want to set.
2. Click Front Destination to display the front destination mesh.
3. Modify the mesh.
4. Copy the front destination mesh and paste it into the back destination mesh for that frame.

   Alternatively, if you want the back destination mesh to always match the front destination mesh, select the Front Destination under Mapped To adjacent to the Back Destination Meshes button.