This chapter represents documentation about mesh decimation. More...

Classes
struct	MR::DecimateSettings
	Parameters structure for MR::decimateMesh. More...
struct	MR::DecimateResult
	Results of MR::decimateMesh. More...
struct	MR::ResolveMeshDegenSettings
struct	MR::RemeshSettings
struct	MR::DecimatePolylineSettings< V >
	Parameters structure for MR::decimatePolyline. More...

Enumerations
enum	MR::DecimateStrategy { MR::MinimizeError , MR::ShortestEdgeFirst }
	Defines the order of edge collapses inside Decimate algorithm. More...
enum class	MR::DecimatePartsMode { MR::DecimatePartsMode::PackedMesh , MR::DecimatePartsMode::AABBTree }
	Defines how decimation finds the parts of the mesh for parallel processing (DecimateSettings::subdivideParts > 1) More...

Functions
DecimateResult	MR::decimateMesh (Mesh &mesh, const DecimateSettings &settings={})
	Performs mesh simplification in mesh region according to the settings.
DecimateResult	MR::decimateObjectMeshData (ObjectMeshData &data, const DecimateSettings &settings)
std::optional< ObjectMeshData >	MR::makeDecimatedObjectMeshData (const ObjectMesh &obj, const DecimateSettings &settings, DecimateResult *outRes=nullptr)
	returns the data of decimated mesh given ObjectMesh (which remains unchanged) and decimation parameters
QuadraticForm3f	MR::computeFormAtVertex (const MeshPart &mp, VertId v, float stabilizer, bool angleWeigted, const UndirectedEdgeBitSet *creases=nullptr)
	Computes quadratic form at given vertex of the initial surface before decimation.
Vector< QuadraticForm3f, VertId >	MR::computeFormsAtVertices (const MeshPart &mp, float stabilizer, bool angleWeigted, const UndirectedEdgeBitSet *creases=nullptr)
	Computes quadratic forms at every vertex of mesh part before decimation.
FaceBitSet	MR::getSubdividePart (const FaceBitSet &valids, size_t subdivideParts, size_t myPart)
	returns given subdivision part of all valid faces; parallel threads shall be able to safely modify these bits because they do not share any block with other parts
bool	MR::resolveMeshDegenerations (Mesh &mesh, const ResolveMeshDegenSettings &settings={})
	Removes degenerate triangles in a mesh by calling decimateMesh function with appropriate settings.
bool	MR::remesh (Mesh &mesh, const RemeshSettings &settings)
	Splits too long and eliminates too short edges from the mesh.
DecimatePolylineResult	MR::decimatePolyline (Polyline2 &polyline, const DecimatePolylineSettings2 &settings={})
	Collapse edges in the polyline according to the settings.
DecimatePolylineResult	MR::decimateContour (Contour2f &contour, const DecimatePolylineSettings2 &settings={})
	Collapse edges in the contour according to the settings.

Detailed Description

This chapter represents documentation about mesh decimation.

Enumeration Type Documentation

◆ DecimatePartsMode

enum class MR::DecimatePartsMode

strong

#include <MRMesh/MRMeshDecimate.h>

Defines how decimation finds the parts of the mesh for parallel processing (DecimateSettings::subdivideParts > 1)

Enumerator
PackedMesh	the mesh is already packed optimally (e.g. by mesh.packOptimally()), and the parts are ranges of face ids
AABBTree	the parts are subtrees of mesh's AABB tree (taken from the mesh if present, otherwise constructed), no packing is needed; the number of parts is rounded up to a power of two

◆ DecimateStrategy

enum MR::DecimateStrategy

#include <MRMesh/MRMeshDecimate.h>

Defines the order of edge collapses inside Decimate algorithm.

Enumerator
MinimizeError	the next edge to collapse will be the one that introduced minimal error to the surface
ShortestEdgeFirst	the next edge to collapse will be the shortest one

Function Documentation

◆ computeFormAtVertex()

QuadraticForm3f MR::computeFormAtVertex	(	const MeshPart &	mp,
		VertId	v,
		float	stabilizer,
		bool	angleWeigted,
		const UndirectedEdgeBitSet *	creases = nullptr )

nodiscard

#include <MRMesh/MRMeshDecimate.h>

Computes quadratic form at given vertex of the initial surface before decimation.

◆ computeFormsAtVertices()

Vector< QuadraticForm3f, VertId > MR::computeFormsAtVertices	(	const MeshPart &	mp,
		float	stabilizer,
		bool	angleWeigted,
		const UndirectedEdgeBitSet *	creases = nullptr )

nodiscard

#include <MRMesh/MRMeshDecimate.h>

Computes quadratic forms at every vertex of mesh part before decimation.

◆ decimateContour()

DecimatePolylineResult MR::decimateContour	(	Contour2f &	contour,
		const DecimatePolylineSettings2 &	settings = {} )

#include <MRMesh/MRPolylineDecimate.h>

Collapse edges in the contour according to the settings.

◆ decimateMesh()

DecimateResult MR::decimateMesh	(	Mesh &	mesh,
		const DecimateSettings &	settings = {} )

#include <MRMesh/MRMeshDecimate.h>

Performs mesh simplification in mesh region according to the settings.

A closed tetrahedron is never collapsed in two triangles lying on each other: it is removed completely if its four vertices can be collapsed in one point within maxError (for ShortestEdgeFirst: none of its edges is longer than maxError), and preCollapse, the limits on deleted faces and vertices, region, fixed boundary vertices, notFlippable and edgesToCollapse permit it; otherwise it is kept whole.

    // Repack mesh optimally without building an AABB tree, which decimation invalidates anyway.
    // It's not necessary but highly recommended to achieve the best performance in parallel processing
    mesh.packOptimally( false );
 
    // Setup decimate parameters
    MR::DecimateSettings settings;
 
    // Decimation stop thresholds, you may specify one or both
    settings.maxDeletedFaces = 1000; // Number of faces to be deleted
    settings.maxError = 0.05f; // Maximum error when decimation stops
 
    // Number of parts for parallel processing, greatly improves performance at the cost of minor quality loss.
    // 16 is a good choice even with fewer CPU cores, since smaller parts are processed faster; much larger values add per-part overhead
    settings.subdivideParts = 16;
 
    // Decimate mesh
    MR::decimateMesh( mesh, settings );

Before

After

◆ decimateObjectMeshData()

DecimateResult MR::decimateObjectMeshData	(	ObjectMeshData &	data,
		const DecimateSettings &	settings )

#include <MRMesh/MRMeshDecimate.h>

Performs mesh simplification with per-element attributes according to given settings;

settings.region limits the simplification like in decimateMesh (whole mesh if null), and face selection is not used as a region; the attributes without values for some mesh elements are padded with default values (see resizeAttributesToMesh)

◆ decimatePolyline()

DecimatePolylineResult MR::decimatePolyline	(	Polyline2 &	polyline,
		const DecimatePolylineSettings2 &	settings = {} )

#include <MRMesh/MRPolylineDecimate.h>

Collapse edges in the polyline according to the settings.

◆ getSubdividePart()

FaceBitSet MR::getSubdividePart	(	const FaceBitSet &	valids,
		size_t	subdivideParts,
		size_t	myPart )

nodiscard

#include <MRMesh/MRMeshDecimate.h>

returns given subdivision part of all valid faces; parallel threads shall be able to safely modify these bits because they do not share any block with other parts

◆ makeDecimatedObjectMeshData()

std::optional< ObjectMeshData > MR::makeDecimatedObjectMeshData	(	const ObjectMesh &	obj,
		const DecimateSettings &	settings,
		DecimateResult *	outRes = nullptr )

nodiscard

#include <MRMesh/MRMeshDecimate.h>

returns the data of decimated mesh given ObjectMesh (which remains unchanged) and decimation parameters

◆ remesh()

bool MR::remesh	(	Mesh &	mesh,
		const RemeshSettings &	settings )

#include <MRMesh/MRMeshDecimate.h>

Splits too long and eliminates too short edges from the mesh.

◆ resolveMeshDegenerations()

bool MR::resolveMeshDegenerations	(	Mesh &	mesh,
		const ResolveMeshDegenSettings &	settings = {} )

#include <MRMesh/MRMeshDecimate.h>

Removes degenerate triangles in a mesh by calling decimateMesh function with appropriate settings.

consider using fixMeshDegeneracies for more complex cases

Returns: true if the mesh has been changed

See also: decimateMesh

Classes

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ DecimatePartsMode

◆ DecimateStrategy

Function Documentation

◆ computeFormAtVertex()

◆ computeFormsAtVertices()

◆ decimateContour()

◆ decimateMesh()

◆ decimateObjectMeshData()

◆ decimatePolyline()

◆ getSubdividePart()

◆ makeDecimatedObjectMeshData()

◆ remesh()

◆ resolveMeshDegenerations()