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Surface Tools


Blend Surface

 History enabled

The BlendSrf command creates a transitional surface between two surface, polysurface, or extrusion edges.


  1. Select the first edge.

    Use the ChainEdges option to select an edge chain.

  2. Select the second edge, or another edge chain.

  3. Adjust the blend settings or handle control points, click OK.

Command-line option


Selects connected edges that will be considered a single edge.

How to chain select edges.


Changes the blend settings and handles for the blend surface created with History.

History locking temporarily turns off when editing a blend surface with History.

Keys for control


By default the shape curves are separately edited at each end, Hold Shift to retain symmetry. With symmetry, point editing is mirrored to the other end of the curve.


Hold Alt while dragging the handles to change the angle between the shape curve and the surface edge.

  • By default the shape curves are perpendicular to the surface edge or parallel to the surface isocurves.
  • If the edge is trimmed, the shapes are perpendicular to the surface edge.
  • If the edge is untrimmed, the shapes are parallel to the surface isocurves.

To adjust seams

  1. Select each seam point and move it along the curve to line up all curve seams.

  2. Use the Flip option to make all seam arrows point to the same side.

  3. Press Enter to continue.

Adjust seam options (Closed curves only)


Reverses the curve direction.


Attempts to align the seam points and directions without intervention.


Moves the seam points to the way they were at the beginning of the command.

Adjust Surface Blend options


Maintains the relationship between the two curve ends.


Determines the distance of influence the surface has on the edge curve.

Sliders (2) control each surface end.
Lock sliders icon (1), surface end bulge controls (2).
Continuity options

Sets the continuity for each surface end.






Add Shapes

Adds additional curve profile shapes to increase control over the blend surface shape. This is especially important if the input shapes are complex and you want to control the shape in more locations.

When you snap to a point and add a shape, the command automatically creates a shape that connects to the corresponding point on the other side, which attempts to keep the blend simple.

Remove Shapes

Removes curve profile shapes.


Click to automatically add shapes that make the blend surface isocurves less twisted.


The angle threshold used to evaluate where more shapes are required.

If the angle between the isocurve direction (1) and rail tangent direction (2) is less than the angle threshold, a shape will be added. When a shape is added, the surface is rebuilt and then re-evaluated.

Interior shapes

Turns on or off including all of the shapes at Greville points for simple blends. The use of interior shapes takes the entire surface edge selection taken into account for continuity.

The Interior shapes and Refine checkboxes cannot be enabled at the same time.


Avoids creating a simpler blend surface when it is possible to do. More isocurves will be added to the blend surface.

Planar sections

Forces all shape curves to be planar and parallel to the specified direction.

Same height

If the gaps between the surfaces vary, this option maintains the height of the shape curves throughout the blend.



See also


Visually evaluate surface smoothness and continuity using a stripe map.

Fillet, blend, or chamfer between curves and surfaces

BlendSrf History




Rhinoceros 7 © 2010-2023 Robert McNeel & Associates. 03-May-2023