Crease splitting enabled.

The MatchSrf command adjusts the edge of a surface to have position, tangent, or curvature continuity with another surface.


1. Select an untrimmed surface edge.
2. Select a surface edge or curve to match.

Pick the two surfaces near same ends. This surface can be either trimmed or untrimmed.

3. Choose options.

Command-line options


Allows selection of more than one edge to match.


Selects surface edges that are touching the selected curve.

Match Surface Options


Sets the continuity for the match.


Location only.


Position and direction.


Position, direction, and radius of curvature.

Preserve other end

Changes the surface structure to prevent modification of the curvature at the edge opposite the match.


No constraint.


Location only.


Position and curve direction.


Position, direction, and radius of curvature.

Average surfaces

Both surfaces are modified to an intermediate shape. If the target surface is also untrimmed, the surfaces match by averaging the two.

Match edges by closest points

Aligns the surface being changed to the target edge in two ways:

Stretches or compresses the surface to match the entire edge end to end, or pulls each point object on the edge to the closest point object on the other edge.

Refine match

Determines if the match results should be tested for accuracy and refined so the faces match within tolerance. If necessary, Rhino adds knot lines to the modified surface or surfaces until the surfaces are within tolerance.

Distance __ units

Position matching in model units.

Tangency __ degrees

Tangency matching.

Curvature __ percent

Curvature matching, in percent of the radius of curvature.

Isocurve direction adjustment

Specifies the way the parameterization of the matched surfaces is determined.


If the target edge is not trimmed, it works like the Match target isocurve direction option.

If the target edge is trimmed, it works like the Make perpendicular to the target edge option.

Preserve isocurve direction

Does not change the existing isoparametric curves directions.

Match target isocurve direction

The isoparametric curves of the surface will be parallel to those of the target surface.

Make perpendicular to target edge

The isoparametric curves of the surface will be perpendicular to the target surface edge.


The edge of a surface being modified must be an untrimmed edge.
A closed edge cannot be matched to an open edge.
Only single complete edge curves can be matched. If you need to match to part of an edge, trim the surface or split the edge (using the SplitEdge command).
MatchSrf is the most reliable when the surfaces are nearly matched already and require only a small amount of movement to get an accurate match.
MatchSrf can be useful for matches that are more similar to geometry creation than to fine-tuning. It is possible to move edges a long way and change their shape drastically, but it might take some experimenting to get what you want.
You can sometimes change the results of MatchSrf by adding or removing knots manually before you do the match using the InsertKnot and RemoveKnot commands.

See also

Edit surfaces

Rhinoceros 5 © 2010-2015 Robert McNeel & Associates. 17-Sep-2015