Texture mapping subdivision surfaces with hard constraints

We propose a texture mapping technique that allows user to directly manipulate texture coordinates of subdivision surfaces through adding feature correspondences. After features, or constraints, are specified by user on the subdivision surface, the constraints are projected back to the control mesh and a polygon matching/embedding algorithm is performed to generate polygon regions that embed texture coordinates of control mesh into different regions. After this step, some Steiner points are added to the control mesh. The generated texture coordinates exactly satisfy the input constraints but with high distortions. Then a constrained smoothing algorithm is performed to minimize distortions of the subdivision surface via updating texture coordinates of the control mesh. Finally, an Iterative Closest Point (ICP)-based deformation algorithm is performed to remove subdivision errors caused by the added Steiner points.