Methods and apparatus for deactivating internal constraint curves when inflating an N-sided patch

A system, comprising:

• at least one processor;
• a display device;
• and
• a memory comprising program instructions stored thereon that, responsive to execution by the at least one processor, implement a 3D modeling tool, the 3D modeling tool configured to:
• obtain a two-dimensional sketch including a two-dimensional internal constraint curve as an input patch;
• deactivate the internal constraint curve;
• inflate the surface of the patch to generate a three-dimensional surface according to one or more active constraints of the input patch, the 3D modeling tool configured to inflate the surface of the patch by:
• tessellating the surface of the input patch to generate an initial tessellated surface by generating ghost vertices to complete one-ring neighborhoods of boundary vertices of a boundary of the initial tessellated surface;
• specifying a surface normal constraint value at one or more of the boundary vertices of the initial tessellated surface;
• and
• inflating the initial tessellated surface according to the specified surface normal constraint values at the one or more boundary vertices while maintaining the boundary to generate an inflated surface that provides a three-dimensional geometric effect.

A computer-readable storage device comprising program instructions stored thereon that, responsive to execution, perform operations comprising:

• obtaining a two-dimensional sketch including a two-dimensional internal constraint curve as an input patch;
• deactivating the internal constraint curve;
• inflating the surface of the patch to generate a three-dimensional surface according to one or more active constraints of the input patch, the inflating the surface of the patch further comprising:
• tessellating the surface of the input patch to generate an initial tessellated surface by generating ghost vertices to complete one-ring neighborhoods of boundary vertices of a boundary of the initial tessellated surface;
• specifying a surface normal constraint value at one or more of the boundary vertices of the initial tessellated surface;
• and
• inflating the initial tessellated surface according to the specified surface normal constraint values at the one or more boundary vertices while maintaining the boundary to generate an inflated surface that provides a three-dimensional geometric effect;
• and
• during or after the inflating the surface of the patch, reactivating the deactivated internal constraint curve without affecting the surface of the patch.