A datum element does not contain information regarding the operation parameters defined by the command and derived conditions and analyses.
After terminating the command, you have no longer access to these information enabling you to re-compute the created element after modifying the support geometry with Sculpt panel options.
Before you begin: Open a 3DShape containing a surface.
Create a surface of Surf Type: SurfaceCurve using OmniSurf command.
In the OmniSurf panel, select Datum in the Update list in the SoftParametric section.
Click OK.
A datum element is created and Surface.x is added to the tree.
In the Sculpt panel, select Control Points and Continuities, and modify the input surface at the connecting edge.
In the work area, no continuity label is displayed. The flange surface neither can be re-computed nor the matching conditions restored after sculpting the input surface.
using 
command.
and 
, and modify the input surface at the connecting edge.