The Bend sample demonstrates a technique called surface skinning. It displays 3-D object which rotates about the y-axis and appears to bend.
Source: (SDK root)\Samples\Multimedia\D3dim\Src\Bend
Executable: (SDK root)\Samples\Multimedia\D3dim\Bin
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The sample achieves the surface skinning effect by using two static copies of the object, one of which is oscillating along an axis. Each frame, the vertices of the two objects are merged and blended into a third object. The sample program displays the object derived from the third set of vertices.
This sample was built using the Direct3D sample framework.