MatchSrf

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

Command-line options
MultipleMatches	Allows selection of more than one edge to match.
CurveNearSurface	When the CurveNearSurface option is on, you can select a curve that is on or near a surface as the target, and then a surface to match to at that curve. The curve is pulled to the surface. Before match (left); after match (right). Note The match is to the surface as if the pulled curve were an edge. There is no good way to determine, absent a trim, which way the match should go, so the dialog has a Flip button to control the direction of the match. You can also press Enter to skip selecting a target curve and only select a target surface. In that case, the edge to be changed is pulled to the target surface and the pulled curve is used as the target. If the MultipleMatches option is selected, only matching to an edge is allowed. Helmet - MatchSrf - CrvOnSrf
ChainEdges	Selects surface edges that are touching the selected curve. How to chain select edges.
SubCrv	Type subcrv to select part of a curve as input.

Match Surface Options

Continuity

Sets the continuity for the match.

Position

Location only.

Tangency

Position and direction.

Curvature

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.

None

No constraint.

Position

Location only.

Tangency

Position and curve direction.

Curvature

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.

Isocurve direction adjustment

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

Automatic

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.

Note

• 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

Zebra

Edit surfaces

Wikipedia: Tangent