The back source mesh always contains the same number of control points and patches as the front source mesh. Copy the front source mesh to use as a starting point, then adapt the mesh shape to the image at each frame of the back clip.

If you are using the Stabilizer and you need more detail for the back source mesh, add subdivisions to the mesh. Be sure to add the same subdivisions to the front source mesh.

To define the source mesh for the back clip:

1. Go to the first frame of the clip.
2. Click Front Source, then click Copy to copy the front source mesh.
3. In the Morph menu, click Back Source to select the back source mesh.
4. Click Paste to paste the copied mesh into the back source mesh.
5. Click Back to view the back clip.
6. Modify the back source mesh to match the image in the back clip at each frame. You can either modify the mesh manually or use the Stabilizer to track the movement in the back clip.