stlFileChecker

Detect and list bad features of STL files

Description

Use the stlFileChecker object to detect and list bad features in STL files. The bad features you can detect using the stlFileChecker object are:

• Non-manifold edges

• Non-manifold vertices

• Slivers

• Duplicate vertices

• Normal transition edges

• Free triangles

• T-vertices

Creation

Syntax

obj = stlFileChecker(filename)

obj = stlFileChecker(filename,Name=Value)

Description

obj = stlFileChecker(filename) detects bad features in the STL file specified by filename and lists the features in the stlFileChecker object.

obj = stlFileChecker(filename,Name=Value) sets Input Properties using name-value arguments. For example, stlFileChecker('s.stl',ShowLog=1) displays a log of the bad features in file s.stl. You can specify multiple name-value arguments. Properties not specified retain their default values.

Input Arguments

filename — Name of STL file

character vector | string scalar

Name of the STL file, specified as a character vector or string scalar.

Example: S = stlFileChecker('s1.stl')

Properties

Input Properties

ShowLog — Display or hide log of bad features

1 (default) | 0

Display or hide a log of the bad features in the STL file, specified as 1 or 0. Specify 1 to display the log of bad features. Specify 0 to hide the log of bad features.

Example: ShowLog=0

Data Types: logical

MinimumSeparation — Minimum separation between two distinct vertices

1e-6 (default) | positive scalar

Minimum separation between two distinct vertices, specified as a positive scalar in meters. If the distance between two vertices is less than MinimumSeparation, then the object considers the vertices as duplicates. The smallest value that you can specify is 2.5e-7.

Example: MinimumSeparation=2e-6

Data Types: double

MinimumArea — Minimum area of triangle

1e-11 (default) | positive scalar

Minimum area of a triangle, specified as a positive scalar in square meters. If the area of a triangle is less than MinimumArea, then the object considers the triangle as a sliver. The smallest value that you can specify is 2.5e-12.

Example: MinimumArea=3e-10

Data Types: double

Derived Properties

NonManifoldEdges — Edges shared by more than two triangles

positive scalar

This property is read-only.

Edges shared by more than two triangles, returned as a positive scalar.

Data Types: double

NonManifoldVertices — Vertex connected to two or more surfaces

positive scalar

This property is read-only.

Vertex connected to two or more surfaces, returned as a positive scalar. A pair of triangles with a common edge belong to the same surface.

Data Types: double

Slivers — Triangle with area less than MinimumArea

positive scalar

This property is read-only.

Triangle with area less than MinimumArea, returned as a positive scalar.

Data Types: double

DuplicateVertices — Vertices with separation less than MinimumSeparation

positive scalar

This property is read-only.

Vertices with separation less than MinimumSeparation, returned as a positive scalar.

Data Types: double

NormalTransitionEdges — Edges shared by triangles with normals in opposite directions

positive scalar

This property is read-only.

Edges shared by triangles with normals in opposite directions, returned as a positive scalar.

Data Types: double

FreeTriangles — Triangles with no shared vertex

positive scalar

This property is read-only.

Triangles with no shared vertex, returned as a positive scalar.

Data Types: double

TVertices — Edge connected to any point other than end point of triangle

positive scalar

This property is read-only.

Edge connected to any point other than the end point of a triangle, returned as a positive scalar.

Data Types: double

Examples

Detect and Visualize Bad Mesh Features

Use the stlFileChecker object to detect and display bad features in an STL file.

stlFilename = 'sample_stl_file.stl';
s = stlFileChecker(stlFilename)

detected 8 non manifold edges
detected 3 non manifold vertices
detected 0 duplicate Vertices
detected 0 Slivers
detected 12 Normal Transition Edges
detected 2 Free Triangles
detected 9 T-Vertices
detected 4 duplicate Vertices
detected 0 Slivers

s = 
  stlFileChecker with properties:

                 FileName: 'sample_stl_file.stl'
            Triangulation: [162x3 triangulation]
         NonManifoldEdges: [8x2 double]
      NonManifoldVertices: [3x1 double]
                  Slivers: [0x1 double]
        DuplicateVertices: [4x1 double]
    NormalTransitionEdges: [12x2 double]
            FreeTriangles: [2x1 double]
                TVertices: [9x1 double]
                  ShowLog: 1
        MinimumSeparation: 1.0000e-06
              MinimumArea: 1.0000e-11

Visualize the non-manifold edges in the STL file.

showNonManifoldEdges(s)

Visualize the non-manifold vertices in the STL file.

figure
showNonManifoldVertices(s)

Visualize the free triangles in the STL file.

figure
showFreeTriangles(s)

Detect and Visualize T-Vertices

Detect and visualize the T-vertices in an STL file.

s = stlFileChecker('sample_file.stl',ShowLog=0);

Visualize the T-vertices in the STL file.

showTVertices(s)

More About

STL File

An STL file describes the surface geometry of a three-dimensional object as a mesh of triangles. The three elements of a triangle are: edge, vertices, and face. This table shows the bad features in an STL file.

STL Bad Features

Non-manifold edge	Non-manifold vertex	Sliver	Duplicate vertices
Normal transition edge	Free triangle	T-vertex