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April 9, 2018, 10:08 |
SHM Layer Addition Phase
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#1 |
New Member
JD
Join Date: May 2017
Posts: 24
Rep Power: 9 |
Hello All,
I have a poor understanding of SHM's layer addition phase and I was wondering if someone could help me understand what I'm doing wrong. What I observe is that when I run SHM with only layer addition set to true, I see it give me a summary like this: Code:
patch faces layers avg thickness[m] near-wall overall ------ ----- ------ --------- ------- patch1 102704 5 2.93e-05 0.000225 patch2 15564 5 4.43e-05 0.000175 patch3 70691 5 2.79e-05 0.000229 Code:
Layer addition iteration 0 -------------------------- Determining displacement for added points according to pointNormal ... Detected 0 points with point normal pointing through faces. Reset displacement at 0 points to average of surrounding points. displacementMedialAxis : Smoothing using Medial Axis ... displacementMedialAxis : Reducing layer thickness at 0 nodes where thickness to medial axis distance is large displacementMedialAxis : Removing isolated regions ... - if partially extruded faces make angle < 35 - if exclusively surrounded by non-extruded faces displacementMedialAxis : Number of isolated points extrusion stopped : 1671 fieldSmoother : Smoothing field ... Iteration 0 residual 8.234928e-07 displacementMedialAxis : Moving mesh ... displacementMedialAxis : Iteration 0 Moving mesh using displacement scaling : min:1 max:1 Checking faces in error : non-orthogonality > 55 degrees : 0 faces with face pyramid volume < 1e-13 : 0 faces with face-decomposition tet quality < 1e-09 : 0 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.02 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 displacementMedialAxis : Successfully moved mesh displacementMedialAxis : Finished moving mesh ... truncateDisplacement : Unextruded 0 faces due to non-consecutive vertices being extruded. truncateDisplacement : Unextruded 0 faces due to stringed edges with inconsistent extrusion. Setting up information for layer truncation ... Detected 0 baffles across faceZones of type internal Checking mesh with layer ... Checking faces in error : non-orthogonality > 55 degrees : 15148 faces with face pyramid volume < 1e-13 : 11 faces with face-decomposition tet quality < 1e-09 : 2399279 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.02 : 13503 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 576 faces on cells with determinant < 0.001 : 338645 Detected 2767162 illegal faces (concave, zero area or negative cell pyramid volume) Extruding 0 out of 188959 faces (0%). Removed extrusion at 101053 faces. Added 850983 out of 944795 cells (90.07065%). Code:
Checking mesh with layer ... Checking faces in error : non-orthogonality > 55 degrees : 0 faces with face pyramid volume < 1e-13 : 0 faces with face-decomposition tet quality < 1e-09 : 0 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.02 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 Detected 0 illegal faces (concave, zero area or negative cell pyramid volume) Extruding 0 out of 188959 faces (0%). Removed extrusion at 0 faces. Added 0 out of 944795 cells (0%). Edge intersection testing: Number of edges : 2652247 Number of edges to retest : 0 Number of intersected edges : 208633 patch faces layers overall thickness [m] [%] ------ ----- ------ --- --- patch1 102704 0 0 0 patch2 15564 0 0 0 patch3 70691 0 0 0 So, my question is, is there something wrong with the way that I've done my refinementRegions, refinementSurfaces, snapControls, etc.? (Do I have to go coarser, finer, do only refinementRegions, do only explicit edge refinement...?) OR, does it have something to do with the way that I setup my expansionRatio, finalLayerThickness, minThickness, nGrow and the other layer addition settings.? (Do I switch to absolute sizes?...this seems to get me further along the process) OR, does it have something to do with my advanced layer addition settings? (I don't even know how to visualize the Median Axis and the Smooth Surface Normals, etc.) Any help will be appreciated. |
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October 7, 2018, 16:00 |
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#2 |
Member
Utkun Malkocoglu
Join Date: Feb 2017
Posts: 36
Rep Power: 9 |
I have a similar problem too, even at layer addition iteration 1, I get 0 BL cells on the described patches. My log associated with the problem is below:
Code:
Undo iteration 0 ---------------- Checking faces in error : non-orthogonality > 65 degrees : 0 faces with face pyramid volume < 1e-13 : 21143767 faces with face-decomposition tet quality < 1e-15 : 2 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.05 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 Masters that need to be restored:2596 Edge intersection testing: Number of edges : 21507365 Number of edges to retest : 17244 Number of intersected edges : 1359747 Undo iteration 1 ---------------- Checking faces in error : non-orthogonality > 65 degrees : 0 faces with face pyramid volume < 1e-13 : 21147825 faces with face-decomposition tet quality < 1e-15 : 2 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.05 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 Masters that need to be restored:0 Merging all points on surface that - are used by only two boundary faces and - make an angle with a cosine of more than 0.996195. Removing 807 straight edge points ... Edge intersection testing: Number of edges : 21507365 Number of edges to retest : 3209 Number of intersected edges : 1359747 Undo iteration 0 ---------------- Checking faces in error : non-orthogonality > 65 degrees : 0 faces with face pyramid volume < 1e-13 : 21147825 faces with face-decomposition tet quality < 1e-15 : 2 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.05 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 Detected 0 error faces on boundaries that have been merged. These will be restored to their original faces. Detected 21147827 error faces in mesh. Restoring neighbours of faces in error. Edge intersection testing: Number of edges : 21507365 Number of edges to retest : 20528004 Number of intersected edges : 1359747 Snapped mesh : cells:6725608 faces:21507365 points:8058354 Cells per refinement level: 0 99250 1 252287 2 289967 3 1005846 4 5078258 Writing mesh to time 0.00016 Wrote mesh in = 271.07 s. Mesh snapped in = 20278.5 s. Shrinking and layer addition phase ---------------------------------- Using mesh parameters { maxNonOrtho 65; maxBoundarySkewness 20; maxInternalSkewness 4; maxConcave 80; minVol 1e-13; minTetQuality 1e-15; minArea -1; minTwist 0.02; minDeterminant 0.001; minFaceWeight 0.05; minVolRatio 0.01; minTriangleTwist -1; nSmoothScale 4; errorReduction 0.75; relaxed { maxNonOrtho 75; } } Merging all faces of a cell --------------------------- - which are on the same patch - which make an angle < 150 degrees (cos:-0.866025) - as long as the resulting face doesn't become concave by more than 90 degrees (0=straight, 180=fully concave) Merging 54288 sets of faces. Edge intersection testing: Number of edges : 21450515 Number of edges to retest : 221962 Number of intersected edges : 1302897 Undo iteration 0 ---------------- Checking faces in error : non-orthogonality > 65 degrees : 0 faces with face pyramid volume < 1e-13 : 21091197 faces with face-decomposition tet quality < 1e-15 : 2 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.05 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 Masters that need to be restored:54286 Edge intersection testing: Number of edges : 21507363 Number of edges to retest : 278802 Number of intersected edges : 1359745 Undo iteration 1 ---------------- Checking faces in error : non-orthogonality > 65 degrees : 0 faces with face pyramid volume < 1e-13 : 21147825 faces with face-decomposition tet quality < 1e-15 : 2 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.05 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 Masters that need to be restored:0 Merging all points on surface that - are used by only two boundary faces and - make an angle with a cosine of more than -0.866025. No straight edges simplified and no points removed ... Checking mesh manifoldness ... Outside of mesh is multiply connected across edges or points. This is not a fatal error but might cause some unexpected behaviour. Checking initial mesh ... Checking faces in error : non-orthogonality > 65 degrees : 0 faces with face pyramid volume < 1e-13 : 21147825 faces with face-decomposition tet quality < 1e-15 : 2 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.05 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 Detected 21147827 illegal faces (concave, zero area or negative cell pyramid volume) Doing initial balancing ----------------------- Found 0 zoned faces to keep together. Found 0 separated coupled faces to keep together. Adding in total 0 inter-processor patches to handle extrusion of non-manifold processor boundaries. Handling points with inconsistent layer specification ... Handling non-manifold points ... Checking patch manifoldness ... Outside of local patch is multiply connected across edges or points at 261 points. Set displacement to zero for all 261 non-manifold points Handling feature edges ... patch faces layers avg thickness[m] near-wall overall ----- ----- ------ --------- ------- l1.stl 91400 16 1.39e-05 0.000233 l2.stl 415018 16 1.39e-05 0.000233 l3.stl 758786 16 1.39e-05 0.000233 Selecting externalDisplacementMeshMover displacementMedialAxis displacementMedialAxis : Calculating distance to Medial Axis ... displacementMedialAxis : Smoothing normals ... Iteration 0 residual 0.00249261 displacementMedialAxis : Limited walk to 10 steps. Not visited 504388 out of 8306180 points displacementMedialAxis : Inserting points on patch inlet if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch outlet if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch bottom if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch top if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch backWall.stl if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch frontWall.stl if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch inlet.stl if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch outlet.stl if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch u1.stl if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch u2.stl if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Inserting points on patch u3.stl if angle to nearest layer patch > 30 degrees. displacementMedialAxis : Smoothing normals in interior ... Iteration 0 residual 0.00669688 Layer addition iteration 0 -------------------------- Determining displacement for added points according to pointNormal ... Detected 0 points with point normal pointing through faces. Reset displacement at 0 points to average of surrounding points. displacementMedialAxis : Smoothing using Medial Axis ... displacementMedialAxis : Reducing layer thickness at 0 nodes where thickness to medial axis distance is large displacementMedialAxis : Removing isolated regions ... displacementMedialAxis : Number of isolated points extrusion stopped : 0 displacementMedialAxis : Smoothing field ... Iteration 0 residual 0 Iteration 10 residual 0 displacementMedialAxis : Moving mesh ... displacementMedialAxis : Iteration 0 Moving mesh using displacement scaling : min:1 max:1 Checking faces in error : non-orthogonality > 65 degrees : 0 faces with face pyramid volume < 1e-13 : 20649922 faces with face-decomposition tet quality < 1e-15 : 2 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.05 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 displacementMedialAxis : Successfully moved mesh displacementMedialAxis : Finished moving mesh ... truncateDisplacement : Unextruded 0 faces due to non-consecutive vertices being extruded. truncateDisplacement : Unextruded 0 faces due to stringed edges with inconsistent extrusion. Setting up information for layer truncation ... Checking mesh with layer ... Checking faces in error : non-orthogonality > 65 degrees : 0 faces with face pyramid volume < 1e-13 : 20649922 faces with face-decomposition tet quality < 1e-15 : 2 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.05 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 Detected 20649924 illegal faces (concave, zero area or negative cell pyramid volume) Extruding 0 out of 1265204 faces (0%). Removed extrusion at 0 faces. Added 0 out of 20243264 cells (0%). Edge intersection testing: Number of edges : 21507363 Number of edges to retest : 0 Number of intersected edges : 1359745 Doing final balancing --------------------- Writing 0 added cells to cellSet addedCells Writing 0 faces inside added layer to faceSet layerFaces Writing fields with layer information: nSurfaceLayers : actual number of layers thickness : overall layer thickness thicknessFraction : overall layer thickness (fraction of desired thickness) patch faces layers overall thickness [m] [%] ----- ----- ------ --- --- l1.stl 91400 0 0 0 l2.stl 415018 0 0 0 l3.stl 758786 0 0 0 Removing zero-sized patches: inlet type patch at position 0 outlet type patch at position 1 front_back type empty at position 2 bottom type wall at position 3 top type patch at position 4 Layer mesh : cells:6725608 faces:21507363 points:8058354 Cells per refinement level: 0 99250 1 252287 2 289967 3 1005846 4 5078258 Writing mesh to time 0.00024 Wrote mesh in = 459.69 s. Layers added in = 459.69 s. Checking final mesh ... Checking faces in error : non-orthogonality > 65 degrees : 0 faces with face pyramid volume < 1e-13 : 21148970 faces with face-decomposition tet quality < 1e-15 : 2 faces with concavity > 80 degrees : 0 faces with skewness > 4 (internal) or 20 (boundary) : 0 faces with interpolation weights (0..1) < 0.05 : 0 faces with volume ratio of neighbour cells < 0.01 : 0 faces with face twist < 0.02 : 0 faces on cells with determinant < 0.001 : 0 Finished meshing with 21148972 illegal faces (concave, zero area or negative cell pyramid volume) Finished meshing in = 21766.7 s. End Thanks in advance. Last edited by Malkocoglu; October 7, 2018 at 17:38. |
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October 8, 2018, 03:47 |
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#3 | |
New Member
JD
Join Date: May 2017
Posts: 24
Rep Power: 9 |
Quote:
To answer your question, I'm not sure when your illegal faces are being created, but if they're created before your layer addition phase (disable the layer addition phase and run checkMesh), you can extract this set of faces and visualize them in paraView. Sincerely. |
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October 8, 2018, 05:37 |
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#4 | |
Member
Utkun Malkocoglu
Join Date: Feb 2017
Posts: 36
Rep Power: 9 |
Quote:
They are being created since 'Morphing phase'. If I reduce cell numbers in each 3 dims, 'illegal faces are reduced as well. So, I am still wonder why 'faces with face pyramid volume < 1e-13' and illegal faces' are occurred. Thanks. Last edited by Malkocoglu; October 8, 2018 at 09:44. |
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November 1, 2018, 07:05 |
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#5 |
New Member
Ersin
Join Date: Sep 2018
Posts: 9
Rep Power: 8 |
Hi all,
I am trying to add layers to a axis fan which has a complex geometry. After castellation and snapping with sHM, layer addition became an issue for me. I have the same (as I can see) problem as dickcruz has. I guess sHM adds some layers at iteration 0, than after iteration 1, no layer remains at all. There are some other posts in this forum regarding the problems with layer addition. I checked them however they do not help with my issue. Any help or idea will be appriciated. The following is the related part of my sHMDict file Code:
addLayersControls { relativeSizes true; layers { blade_H62X_VP_FAZI_WO_AIS_V0.FAN_BLADE { nSurfaceLayers 2; } blade_H62X_VP_FAZI_WO_AIS_V0.FAN_THIN_PARTS { nSurfaceLayers 3; } } expansionRatio 1.2; finalLayerThickness 0.3; minThickness 0.1; nGrow 1; featureAngle 90; nRelaxIter 3; nSmoothSurfaceNormals 1; nSmoothNormals 3; nSmoothThickness 10; maxFaceThicknessRatio 0.5; maxThicknessToMedialRatio 0.3; minMedianAxisAngle 80; nBufferCellsNoExtrude 0; nLayerIter 50; } |
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Tags |
layer addition, layering, snappy, snappy hex mesh, snappyhexmesh |
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