◦ First direction collector—Displays curve or edge chain references that create a blended surface in the first direction.

▪ Details—Opens the Chain dialog box to edit chain properties.

◦ Second direction collector—Displays curve or edge chain references that create a blended surface in the second direction.

◦ Close blend check box—Forms a closed loop surface by blending the last curve back to the first curve. Only applicable to single direction curves where the other collector is empty.

◦ Boundary list—Lists the chains in the boundary blend.

◦ Condition—Controls the boundary conditions including tangency conditions for edge alignment. Possible conditions for each chain are Free, Tangent, Curvature, and Normal.

◦ Display drag handles check box—Shows drag handles to control the boundary stretch factor.

◦ Add side curve influence check box—Enables side curve influence. In a one-directional blended surface, for boundary conditions specified as Tangent or Curvature, the system makes the side edges of the blended surface tangent to the side edges of the references.

◦ Add inner edge tangency check box—Sets the tangent inner edge condition for one or both directions of a blended surface. This condition applies only to surfaces with multi-segment boundaries. You can create a blended surface with patches that are tangent across inner edges. In some cases, when geometry is complex, dihedral angles at inner edges may deviate from zero.

◦ Optimize surface shape—Smoothes a single surface (not a composite surface) when four boundaries are defined, and tangency (G1) or curvature (G2) connection is applied.

◦ First—Adds or removes control points in the first direction.

◦ Second—Adds or removes control points in the second direction.

◦ Fit—Lists the following predefined control options:

▪ Natural—Blends using the general blending routine and resets the parameters for input curves using the same routine to obtain the best approximation for the surface.

▪ Arclength—Minimal adjustments are made to the original curves. Blends curves using the general blending routine except curves are divided into equal pieces and blended piece-by-piece.

▪ Point to Point—Blends point-by-point. Point 1 in the first curve is connected to point 1 in the second curve and so forth.

▪ Piece to piece—Blends piece-by-piece. Curve chains or composite curves are connected.

▪ Developable—If two tangent curves in one direction are selected, you can toggle to determine if you want the developable option or not.

◦ Sets list—Lists sets of control points.

▪ New Set—Adds a new set of control points.

◦ Control points—Shapes the surface by mapping control point locations on input curves.

◦ Influencing curves collector—Displays curve chains to influence the shape of the blended surface or approximate direction.

▪ Details—Opens the Chain dialog box so you can modify the chain set properties.

◦ Smoothness Factor—Controls the surface roughness, irregularities, or projections.

◦ Patches in direction (First and Second)—Controls the number of patches along u- and v- directions used to form the resultant surface.

◦ Name box—Sets a name for a feature.

• First Direction Curves—Creates a surface feature by specifying bounding curves, edges, or datum points in one direction.

• Second Direction Curves—Creates a surface feature by specifying bounding curves, edges, or datum points in two directions.

• Influencing Curves—Creates a blended surface using boundary curves or edges and additional curves. The system evaluates the curves or edges and creates a blended surface approximating the reference entities, and it allows you to control the amount of deviation from the curves.

• Control Points—Adds control points to control the shape of the blended surface.

• Clear—Removes all items from the active collector.

• Free—No tangency conditions are set along the boundary.

• Tangent—The blended surface is tangent to the reference surface along the boundary.

• Curvature—The blended surface has curvature continuity across the boundary.

• Normal—The blended surface is normal to the reference surface or datum plane.