Creo Interactive Surface Design (Style) > Surfaces > Trimmed Surfaces > About Trimming Surfaces
  
About Trimming Surfaces
In Style, you can trim surfaces and quilts using a set of curves. You can keep or delete the resulting trimmed quilt pieces. By default, Style does not delete any of the trimmed pieces.
 
Trimming a surface does not change its parametric definition. Any soft points or COS do not change after the trim operation.
The curves that you select for trimming surfaces must lie on the quilts.
When using the trim operation, you can:
Use an already trimmed surface for another trim operation. Style allows nested trim operations.
Create COS, dropped curves, and soft points on the trimmed surfaces.
Create connections across the trim boundaries.
Use the Entity Information and Feature Information tools in the Operations group for information about the trimmed surfaces.
Use the tools in the Analysis group for analysis of the trimmed surfaces.