stlFileChecker

Detect and list bad features of STL files

Since R2021b

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

example

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

example

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

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`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

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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

Object Functions

`showDuplicateVertices`	Highlight duplicate vertices in STL file
`showFreeTriangles`	Highlight free triangles in STL file
`showNonManifoldEdges`	Highlight non-manifold edges in STL file
`showNonManifoldVertices`	Highlight non-manifold vertices in STL file
`showNormalTransitionEdges`	Highlight normal transition edges in STL file
`showSlivers`	Highlight slivers in STL file
`showTVertices`	Highlight T-vertices in STL file

Examples

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Detect and Visualize Bad Mesh Features

Open Live Script

Use the stlFileChecker object to detect and display bad features in a 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)

Figure contains an axes object. The axes object with title Mesh showing Non Manifold Edges contains 3 objects of type patch, line. One or more of the lines displays its values using only markers This object represents Non Manifold Edges.

Visualize the non-manifold vertices in the STL file.

figure
showNonManifoldVertices(s)

Figure contains an axes object. The axes object with title Mesh showing Non Manifold Vertices contains 2 objects of type patch, line. One or more of the lines displays its values using only markers This object represents Non Manifold Vertices.

Visualize duplicate vertices in the STL file.

figure
showDuplicateVertices(s)

Figure contains an axes object. The axes object with title Mesh showing Duplicate Vertices contains 2 objects of type patch, line. One or more of the lines displays its values using only markers This object represents Duplicate Vertices.

Visualize the normal transition edges in the STL file.

figure
showNormalTransitionEdges(s)

Figure contains an axes object. The axes object with title Mesh showing Normal Transition Edges contains 3 objects of type patch, line. One or more of the lines displays its values using only markers This object represents Normal Transition Edges.

Visualize the free triangles in the STL file.

figure
showFreeTriangles(s)

Figure contains an axes object. The axes object with title Mesh showing Free Triangles contains 3 objects of type patch, line. One or more of the lines displays its values using only markers This object represents Free Triangles.

Visualize the T-vertices in the STL file.

figure
showTVertices(s)

Figure contains an axes object. The axes object with title Mesh showing T-Vertices contains 2 objects of type patch, line. One or more of the lines displays its values using only markers This object represents T-Vertices.

Detect and Visualize T-Vertices

Open Live Script

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

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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 edges