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inOutStatus

(Not recommended) Status of triangles in 2-D constrained Delaunay triangulation

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inOutStatus(DelaunayTri) is not recommended. Use isInterior(delaunayTriangulation) instead.

DelaunayTri is not recommended. Use delaunayTriangulation instead.

Syntax

IN = inOutStatus(DT)

Description

IN = inOutStatus(DT) returns the in/out status of the triangles in a 2-D constrained Delaunay triangulation of a geometric domain. The i'th triangle in the triangulation is classified as inside the domain if IN(i) = 1 and outside otherwise.

Note

inOutStatus is only relevant for 2-D constrained Delaunay triangulations where the imposed edge constraints bound a closed geometric domain.

example

Examples

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Open Live Script

Create a geometric domain that consists of a square with a square hole.

outerprofile = [-5 -5; -3 -5; -1 -5; 1 -5; 3 -5; ...
 5 -5; 5 -3; 5 -1; 5 1; 5 3;...
 5 5; 3 5; 1 5; -1 5; -3 5; ...
 -5 5; -5 3; -5 1; -5 -1; -5 -3; ];
innerprofile = outerprofile.*0.5;
profile = [outerprofile; innerprofile];
outercons = [(1:19)' (2:20)'; 20 1;];
innercons = [(21:39)' (22:40)'; 40 21];
edgeconstraints = [outercons; innercons];

Create a constrained Delaunay triangulation of the domain.

dt = DelaunayTri(profile,edgeconstraints);

Create two plots: one showing the interior and exterior triangles with respect to the domain, and one that uses inOutStatus to plot the interior triangles only.

subplot(1,2,1)
triplot(dt)
hold on
plot(dt.X(outercons',1),dt.X(outercons',2),...
     '-r','LineWidth',2) 
plot(dt.X(innercons',1),dt.X(innercons',2),...
     '-r','LineWidth',2)
axis equal
hold off
subplot(1,2,2)
inside = inOutStatus(dt);
triplot(dt(inside,:),dt.X(:,1),dt.X(:,2))
hold on
plot(dt.X(outercons',1),dt.X(outercons',2),...
     '-r','LineWidth',2)
plot(dt.X(innercons',1),dt.X(innercons',2),...
     '-r','LineWidth',2);
axis equal
hold off

Figure contains 2 axes objects. Axes object 1 contains 3 objects of type line. Axes object 2 contains 3 objects of type line.

Input Arguments

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Delaunay triangulation representation, specified as a DelaunayTri object.

Tips

  • inOutStatus can produce incorrect or inconsistent results when boundary constraints intersect or overlap. To avoid this behavior, use constraints that form one or multiple closed boundaries that do not intersect or overlap. When boundary constraints are nested without intersections or overlaps, the inside or outside status alternates across the boundaries.

Version History

Introduced in R2009a

See Also

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