NX Cutting an Undercut Region with a T-Cutter

A T-slot cutter with a full radius  will be used to mill an undercut. 

  A Fixed Axis operation with a Surface Area or a Streamline Drive Method is used. After the drive is selected the Preview Display is pressed to see the drive points.

 When the operation is generated the tool is cutting on top of the part. What happened?

By default the Projection Vector is set to Tool Axis. This causes the drive point to be projected onto the top of the part.

Setting the Projection Vector to Normal to Part causes the drive points to be correctly projected onto the undercut region.