Knots are parameter lines at which the underlying surface patches join to form the surface. Knots are displayed graphically as isoparametric lines drawn on the surface. You can drag surface knots or merge them with the knots of an adjacent surface.

When you merge the knots of two surfaces, knots are added to the child surface. They are placed in alignment with the knots of the parent surface. You can merge knots on surfaces with untrimmed edges, or you can merge Curves on Surface (COS) that lie on isolines. You can also replace the knots of a child surface with the knots of a neighboring parent surface.

Select the Keep Base Surface check box to preserve the original knots as you edit. Keeping the base knots better preserves the original shape, but may result in a heavier surface than desired. Removing the base knots may adversely affect the alignment of a surface to its boundary curves, and therefore its ability to subsequently merge with neighboring surfaces.

When knots are displayed, you can activate or deactivate them to increase or decrease the area of the surface affected by your changes. Active knots are displayed in white and inactive knots are displayed in green.