CavityOp

CavityOp tells CavityManager what kind of cavity to create around a seed element. It is a compile-time template argument:

CavityManager<blockThreads, CavityOp::E> cavity(
    block, context, shrd_alloc, true);

The first letter is the seed element type. The second letter, when present, describes the neighboring element type pulled into the deleted region. For example, EV starts from an edge and removes the edge-vertex neighborhood.

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Enum

From include/rxmesh/types.h:

enum class CavityOp
{
    V  = 0,
    E  = 1,
    F  = 2,
    VV = 3,
    VE = V,
    VF = V,
    FV = 4,
    FE = 5,
    FF = FE,
    EV = 6,
    EE = 7,
    EF = E,
};

Some names are aliases because deleting one type already implies deleting another. For example, removing a vertex also removes the incident edges and faces, so VE aliases V.

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Common Choices

Most dynamic mesh kernels start with these choices:

Edit	CavityOp	Seed	Fill-in example
Edge split	E	EdgeHandle	Add one midpoint vertex, connect it to the four boundary vertices, and create four faces.
Edge flip	E	EdgeHandle	Add the opposite diagonal and create the two replacement faces.
Edge collapse	EV	EdgeHandle	Add one merged vertex, connect it to the boundary loop, and create a fan of faces.
Face-edge local edit	FE	FaceHandle	Remove a face-edge stencil and refill it with custom topology.

The same cavity operation can support different edits. Edge split and edge flip both use CavityOp::E since they differ only in how the fill-in reconnects the four boundary vertices.

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Seed Handle Type

The seed passed to create(...) should match the source element of the operation:

Source	Example ops	Seed handle
Vertex	V, VV, VE, VF	VertexHandle
Edge	E, EV, EE, EF	EdgeHandle
Face	F, FV, FE, FF	FaceHandle

for_each_edge(cavity.patch_info(), [&](EdgeHandle eh) {
    if (edge_is_too_long(eh)) {
        cavity.create(eh);  // CavityOp::E or CavityOp::EV
    }
});