How to fix degeneracies in the mesh

[ParvGuptaSpCT]

Hello devs!!

I'm trying to heal degeneracies in my mesh with the following methods.

I checked the documentation and found findDegenerateFaces but nothing to fix them.

hoping for quick response
thanks

[Grantim]

Hello!
For this repair method we use DecimateMesh algorithm with special settings somehow like this:

MeshLib/source/MRMesh/MRMeshDecimate.h

Lines 231 to 241 in 67628a9

	/**
	* \brief Resolves degenerate triangles in given mesh
	* \details This function performs decimation, so it can affect topology
	* \ingroup DecimateGroup
	* \return true if the mesh has been changed
	*
	* \sa \ref decimateMesh
	*/
	MRMESH_API bool resolveMeshDegenerations( Mesh& mesh, const ResolveMeshDegenSettings & settings = {} );
	[[deprecated(" use the version with parameter struct instead" )]]
	MRMESH_API bool resolveMeshDegenerations( Mesh& mesh, int maxIters, float maxDeviation = 0, float maxAngleChange = PI_F / 3, float criticalAspectRatio = 10000 );

MeshLib/source/MRMesh/MRMeshDecimate.cpp

Lines 233 to 243 in 67628a9

	DecimateSettings dsettings
	{
	.maxError = settings.maxDeviation,
	.criticalTriAspectRatio = settings.criticalAspectRatio,
	.tinyEdgeLength = settings.tinyEdgeLength,
	.stabilizer = settings.stabilizer,
	.optimizeVertexPos = false, // this decreases probability of normal inversion near mesh degenerations
	.region = settings.region,
	.maxAngleChange = settings.maxAngleChange
	};
	return decimateMesh( mesh, dsettings ).vertsDeleted > 0;

Enabling subdivide also make the program call subdivideMesh algorithm https://github.com/MeshInspector/MeshLib/blob/master/source/MRMesh/MRMeshSubdivide.h

Forced fix is applied on last iteration if enabled, it removes areas near degenerations and fills it with new triangulation, this discussion might be helpful for understanding "forced" mode: #3853

[ParvGuptaSpCT]

@Grantim , Thanks for the quick reply!!
can you please share a python code snippet for reference

Thanks

[Grantim]

Sure, some examples might be found here:
https://github.com/MeshInspector/MeshLib/blob/master/test_python/test_decimate.py
https://github.com/MeshInspector/MeshLib/blob/master/test_python/test_subdivider.py

Also, please check our documentation page:
https://meshlib.io/documentation/ExampleMeshDecimate.html

Note that our python API is nearly identical to c++, so any documentation found in c++ can be applied to python and vice versa

[ParvGuptaSpCT]

thanks @Grantim