[anu.raghun]

Hi everyone,
I'm having trouble running surfaceFeatureExtract on an stl file? When I try to run it, I get the following error:

Reading surfaceFeatureExtractDict

Surface : "deltaPlate30deg.stl"


Feature line extraction is only valid on closed manifold surfaces.


--> FOAM FATAL ERROR:
while error on line 1
expected but found '�@h�q(�B'

From function int STLLexer::lex()
in file triSurface/interfaces/STL/readSTLASCII.L at line 360.

FOAM exiting

I'm not sure what the error is here? Is it to do with my STL file?
Here is my surfaceFeatureExtractDict:

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

deltaPlate30deg.stl
{
// How to obtain raw features (extractFromFile || extractFromSurface)
extractionMethod extractFromSurface;

extractFromSurfaceCoeffs
{
// Mark edges whose adjacent surface normals are at an angle less
// than includedAngle as features
// - 0 : selects no edges
// - 180: selects all edges
includedAngle 120;
}

// Write options

// Write features to obj format for postprocessing
writeObj yes;
}


surface2.nas
{
// How to obtain raw features (extractFromFile || extractFromSurface)
extractionMethod extractFromFile;

extractFromFileCoeffs
{
// Load from an existing feature edge file
featureEdgeFile "constant/triSurface/featureEdges.nas";
}

trimFeatures
{
// Remove features with fewer than the specified number of edges
minElem 0;

// Remove features shorter than the specified cumulative length
minLen 0.0;
}

subsetFeatures
{
// Use a plane to select feature edges
// (normal)(basePoint)
// Keep only edges that intersect the plane will be included
plane (1 0 0)(0 0 0);

// Select feature edges using a box
// (minPt)(maxPt)
// Keep edges inside the box:
insideBox (0 0 0)(1 1 1);
// Keep edges outside the box:
outsideBox (0 0 0)(1 1 1);

// Keep nonManifold edges (edges with >2 connected faces where
// the faces form more than two different normal planes)
nonManifoldEdges yes;

// Keep open edges (edges with 1 connected face)
openEdges yes;
}

addFeatures
{
// Add (without merging) another extendedFeatureEdgeMesh
name axZ.extendedFeatureEdgeMesh;

// Optionally flip features (invert all normals, making
// convex<->concave etc)
//flip false;
}

// Output the curvature of the surface
curvature no;

// Output the proximity of feature points and edges to each other
featureProximity no;
// The maximum search distance to use when looking for other feature
// points and edges
maxFeatureProximity 1;

// Out put the closeness of surface elements to other surface elements.
closeness no;

// Write options

// Write features to obj format for postprocessing
writeObj yes;

// Write surface proximity and curvature fields to vtk format
// for postprocessing
writeVTK no;
}


// ************************************************** *********************** //

I'd appreciate any advice!

[Antimony]

Hi,

Is your STL file encoded in binary? Can you try running the same with an ASCII version of the STL file instead?

Cheers,
Antimony

[anu.raghun]

Thanks for your reply!
It already appears to be ASCII encoded. Is there something else I can do?

[anu.raghun]

Quick update: I used surfaceMeshConvert on my STL file. More bugs followed, but the STL file was able to be read. New thread here.

[afmoh]

I am having the same issue and tried changing the davinci.STL to davinci.stl and it still doesn't work could any one help me

[acsj076@solon mesh1]$ surfaceFeatureExtract
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5.x |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 5.x-73d878406f6b
Exec : surfaceFeatureExtract
Date : Feb 20 2020
Time : 14:27:55
Host : "solon.cluster.intern"
PID : 9712
I/O : uncollated
Case : /home/acsj076/mesh1
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Reading surfaceFeatureExtractDict

Surface : "davinci.stl"


Feature line extraction is only valid on closed manifold surfaces.


--> FOAM FATAL ERROR:
Cannnot read "/home/acsj076/mesh1/constant/triSurface/davinci.stl"

From function bool Foam::triSurface::read(const Foam::fileName&, const Foam::word&, bool)
in file triSurface/triSurface.C at line 360.

FOAM exiting

[acsj076@solon mesh1]$

I have attached the surface Feature Extract Dict below :
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object surfaceFeatureExtractDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

davinci.stl
{
// How to obtain raw features (extractFromFile || extractFromSurface)
extractionMethod extractFromSurface;

extractFromSurfaceCoeffs
{
// Mark edges whose adjacent surface normals are at an angle less
// than includedAngle as features
// - 0 : selects no edges
// - 180: selects all edges
includedAngle 180;
}

subsetFeatures
{
// Keep nonManifold edges (edges with >2 connected faces)
nonManifoldEdges yes;

// Keep open edges (edges with 1 connected face)
openEdges yes;
}


// Write options

// Write features to obj format for postprocessing
writeObj yes;
}


// ************************************************** *********************** //

[Tariq Javaid]

Dear forum members

I am trying to conduct simulation using Open foam. As I tend to extract features of geometry using surfacefeatureextract command, there comes an error "Feature line extraction is only valid on closed manifold surfaces". Is there any problem in .STL file or something else?

[Bob Tipton]

The
"Note: Feature line extraction only valid on closed manifold surfaces"


message is saying you have no solids loaded.

There is no message to tell you no files were read. So, if no files were read it shows this message. I assume if your files have no contents, it will also show this message.

If you search long enough, it will tell you that your stl files must be in
<case dir>/constant/triSurface. If you don't have that folder, it will not report that as an error either.


This is not the worst CAE error message I've ever seen. That was

"An astute user with a flowchart may be able to determine the cause of this error."

Which I translated as the programmer saying "We don't know why we get this error either." In that case they were using a Secant Method root finder and the curve ran out of bounds.