What Is the Difference Between Grid and Mesh?

What Is the Difference Between Grid and Mesh?
What is the difference between grid and mesh? Image link: https://en.wikipedia.org/wiki/Toronto
C O N T E N T S:

KEY TOPICS

  • If mbackgen 3 then generate only an initial triangulation of the boundary points and sources (if any) without a recovered boundary grid and return background grid and length-scale function data through the API. No other mesh generation is done.(More…)
  • I.e. one can first multiply by the difference between the grid points, effectively scaling the output, and then add the offset of the grid.(More…)

POSSIBLY USEFUL

  • If the BC_IDs and Grid_BC_Flag parameter vectors are set then the grid BC flag is reset to the values in the Grid_BC_Flag vector for all faces with corresponding surface IDs.(More…)
  • This generates a 3D grid of interpolated Light Probes inside a bounding volume A closed shape representing the edges and faces of a collider or trigger.(More…)
  • The larger the value of this parameter, the smaller that LAMMPS will set the grid size, to achieve the requested accuracy.(More…)

RANKED SELECTED SOURCES

Double click on a snippet to show in context, i.e. with its surrounding text Modes 1) double click snippet to see in context; 2) double click snippet to Share or Publish

KEY TOPICS

If mbackgen 3 then generate only an initial triangulation of the boundary points and sources (if any) without a recovered boundary grid and return background grid and length-scale function data through the API. No other mesh generation is done. [1] With an open BL region grid and an open domain the BL normals remain the same as those implied by the ordering of the input surface mesh. [1]

SAGA GIS : Grid to TIN (Surface Specific Points) function, followed by Export TIN to Stereo Lithography File (STL) function to export the TIN to a mesh format readable by Meshlab. [2] While generating a mesh of NACA2412 airfoil on ANSYS ICEM CFD 14.0, I am supposed to get a grid (i.e. horizontal and vertical lines as pre-mes. [3]

If the grid is not set using the mesh command, this command will also attempt to use the optimal grid that minimizes cost using an estimate given by (Hardy). [4] The mesh keyword sets the grid size for kspace style pppm or msm. [4] With mbackgen4 also return the element neighbor connectivity for the final volume grid (this is the only difference between mbackgen2 and mbackgen4). [1]

I.e. one can first multiply by the difference between the grid points, effectively scaling the output, and then add the offset of the grid. [5] Even though they’re used for similar things, raster and mesh formats have some very fundamental differences (similar to raster and vector images), so there’s no “default” way for converting between the two. [2]

GS. Composite mesh difference methods for elliptic boundary value problems. [6] Internal grid sampling correction has been implemented as part of the export procedure which greatly increases the appropriateness and accuracy of the sampled results values if the 2D grid is rotated though reporting differences may still occur for significant grid rotation or drastically varying export grid size (relative to the source grid size). [7]

POSSIBLY USEFUL

If the BC_IDs and Grid_BC_Flag parameter vectors are set then the grid BC flag is reset to the values in the Grid_BC_Flag vector for all faces with corresponding surface IDs. [1] If the vector Int_IDs is set then the grid boundary condition flag is set to a value of seven, specifying a fixed surface, for all faces with a surface ID in the list and it is set to a magnitude of one, specifying a non-intersecting surface, for all faces with a surface ID not in the list. [1],id_n then this flag will set the grid boundary condition to a value of 7 (denotes a fixed intersecting surface ) for faces with surface IDs id_1 id_2. id_n. [1]

If found the grid BCs specified in the TAGS file will be used. default0 min0 max1 Write_BL_Only BL element output flag. [1] Only applicable if the input grid is a volume grid and not just a surface grid. default1 min0 max1 mdfblminm BL isotropic length scale limiting flag. [1] If mblchki 1 then check BL parameters and input surface grid, output BL parameters after automatic calculation, and exit without generating a volume grid. [1] If this option is selected then the BL parameters and input surface grid will be checked and then the BL parameters after automatic calculation will be output. [1]

If mbackgen 2 then generate an internal background grid and length-scale function using the input surface boundary points and sources (if any). [1] If mbackgen 1 then generate only an initial triangulation of the boundary points and sources (if any) without a recovered boundary grid and write background grid and length-scale function files using internal file writers. [1]

Option Parameters (Rank 4 – Very Rarely Used) ________________________________________________________________________________ BG_Flag Background grid and length-scale function file flag. [1] This is a program parameter. default.b8.ugrid General Parameters (Rank 2 – Sometimes Used) ________________________________________________________________________________ -backgen Generate background grid and length-scale function files. [1]

Equivalent to mblreseti1 No parameter value should be specified. -bls Generate a BL grid from specified surfaces. [1] Equivalent to mbl1 mrecm3 mrecqm3 mblelc2 mquadp1 No parameter value should be specified. -blcheck Check BL parameters and input surface grid. [1] Equivalent to mbl1 mrecm3 mrecqm3 No parameter value should be specified. -blc Generate a BL grid suitable for CFD and create prism elements. [1] Equivalent to mquadp1 No parameter value should be specified. -sls Generate a structured-layer (SL) grid from specified surfaces. [1] Equivalent to SNS_IDs Parameter value must be specified for the last equivalent parameter value. -snsids Generate a SNS grid from specified surfaces. [1]

In boundary-layer (BL) generation mode it also uses the Advancing-Normal Boundary-Layer (ANBL) procedure to generate a tetrahedral/pentahedral/hexahedral BL grid adjacent to BL generating surfaces. [8] Specifies reference Reynolds number per unit grid dimension for determining the parameters that control spacing normal to BL surfaces. [1] If mrecrbf 0 then turn off all reconnection of boundary surface faces regardless of input grid boundary surface face reconnection flag. default1 min0 max1 mrevbl BL normal direction flag. [1] Only applicable if the CFD BL flag is on (mbl1). default2 min0 max2 mchkvoli Input grid volume check flag. [1] Only applicable if the metric space option is on (mmet1 or 2). default1 min0 max2 mbl BL grid flag. [1] Only applicable if the quality improvement re-generation flag is on (mqrgen1). default100 min2 max2000000000 nbld Maximum total BL grid layers allowable. [1] Quality improvement grid re-generation is performed on low-quality element regions with a maximum dihedral angle greater than angqrgen. Only applicable if the quality improvement re-generation flag is on (mqrgen1). default165 min70 max179.9 angqual Final quality dihedral element angle. [1]

The maximum number of initial elements allocated is set to the number of nodes in the boundary grid multiplied by nelpnni. [1] Maximum number of element subdivisions during direct boundary node insertion. default3 min1 max10000000 ninsmaxgg Maximum field grid element subdivisions. [1]

Generate a specified normal spacing (SNS) grid with right-angle elements from all boundary faces with a grid boundary condition flag less than zero. [1] Generate a BL grid suitable for CFD from all boundary faces with a grid boundary condition flag less than zero. [1]

AFLR2/AFLR3 parameter. default1 min0 max3 nbl Maximum BL grid layers to generate. [1] AFLR2/AFLR3 parameter. default5 min2 max100 ngen Maximum number of grid passes. default10000 min0 max10000000 ninsmax Maximum element subdivisions. [1]

A value of cdfr well above a value of 1.0 will decrease the number of grid nodes generated and potentially decrease the element quality. default1.1 min1 max3 cdfrsl -slr SL geometric growth rate. [1],id_n then set the grid boundary condition to a negative value for all faces with surface IDs id_1 id_2. id_n. [1] If msetbc 1, 2, or 3 then check for planar surfaces that are not BL/SL/SNS generating surfaces and automatically set the grid boundary condition flag for them to that for an intersecting surface. [1] If the vector BL_IDs is set then the grid boundary condition flag is set to a negative value, specifying BL grid generation, for all faces with a surface ID in the list and it is set to a positive value, specifying no BL grid generation, for all faces with a surface ID not in the list. [1]

This flag is only applicable in cases with a BL grid (-bl, -bls flag), if the BL velocity profile is assumed to be laminar or turbulent (-blf, -y+, mbltype1, or mbltype2), and if the flow direction vector is specified (-vdir u v w). [1] If mpfrmt 0 then use UG_IO routines to write final output grid to a file of any supported type and format (with increased memory requirements). default4 mrecim Initial local-reconnection flag. [1] If trds 0 then use the initial normal spacing specified in the input surface grid to determine the initial normal spacing for anisotropic transformation on all source type transparent boundary surfaces. [1] The node distribution normal to the boundary surface within a CFD BL grid has iblri layers that use a constant growth rate, cdfrbl. [1] This length scale can be limited by the corresponding minimum isotropic spacing on the BL interface surface as the BL grid is generated. [1] The surface grid will not change and is assumed to intersect the BL for all fixed surfaces that are adjacent to a BL surface. [1] The surface grid will be regenerated with an intersecting BL for all intersecting surfaces that are adjacent to a BL surface. [1]

Equivalent to ngen0 nqual0 mqrgen0 No parameter value should be specified. -no_back Do not read background grid and length-scale function files. [1] Equivalent to mbackgen1 No parameter value should be specified. -backgen2 Generate a background grid and length-scale function internally. [1] Equivalent to mbl2 No parameter value should be specified. -slc Generate a structured-layer (SL) grid and create prismatic elements. [1] Equivalent to Output_File_Flag-2 No parameter value should be specified. -snsc Generate a SNS grid and create prismatic elements. [1] Equivalent to mbl-1 mblelc1 No parameter value should be specified. -snsc2 Generate a SNS grid and create prism/split-hex elements. [1] Equivalent to msource0 No parameter value should be specified. -open Generate an open BL region grid for a closed domain. [1] Equivalent to mtransp4 No parameter value should be specified. -sl Generate a structured-layer grid (SL) grid. [1] Equivalent to mopen2 mrevbl1 No parameter value should be specified. -sns Generate a specified normal spacing (SNS) grid. [1] The specified normal spacing distribution must be set to generate a SNS grid. [1] If mbl -1 then generate layers using specified normal spacing (SNS) next to all boundary faces with a grid boundary condition that is less than zero. [1]

It uses the Advancing-Front/Local-Reconnection (AFLR) procedure to generate a tetrahedral volume grid from an existing surface triangulation. [8] The input surface grid must be periodic if specified to be. [1] If the input surface grid is a non-closed surface then the BL region will be aligned normal to the surface edges. [1] Note that the specified periodic parent and child surfaces must also have a surface grid BC for a surface that intersects the BL region and is rebuilt to match. [1] The output surface grid will maintain the periodic properties specified. [1]

BG_Flag : Background grid and length-scale function file flag. [8] This is a program parameter. default BG_Case_Name -ib -iback -bcase Case name for background grid and function file names. [1] If BG_Flag 0 then do not read background grid and length-scale function files. [1] If mw_func_type 1 then write grid function files using UGRID and SFUNC types. [1] If mw_func_type 2 then write grid function files using MESHB and SOLB types. [1] If mpfrmt 1 then write final output grid to a type UGRID file using formatted ASCII. If mpfrmt 4 then write final grid to a type UGRID file using unformatted binary with floating-point doubles and big endian ordering. [1]

If mrecrbf 1 then allow reconnection of boundary surface faces if allowed by the input grid boundary surface face reconnection flag. [1] Temporary boundary surface FAIL files are exactly the same as the boundary surface FAIL file written after a fatal boundary surface grid error except that they are written out prior to attempting high-risk boundary surface face recovery procedures. [1] Hex elements are generated where possible from boundary surface grid quad faces. [1] The output grid includes a new boundary surface for the exposed surface of the BL region with a boundary surface face ID equal to the maximum ID plus 1. [1] The re-generated grid is accepted if the local maximum dihedral angle is decreased by dangqrgen. Only applicable if the quality improvement re-generation flag is on (mqrgen1). default1 min0 max180 dcdfqrg Re-generation distribution function factor. [1] Only applicable if the quality improvement re-generation flag is on (mqrgen1). default10 min0 max1000000 nqrgen Quality improvement grid re-generation iterations. [1]

If mreciqm 3 then use a combined Delaunay and MAX-MIN-Rratio criterion. default3 min2 max3 msetbc Set grid boundary condition flag option. [1] If msetbc 0 then do not change the input grid boundary condition flag. [1] If mqrgen 1 then low-quality regions of the grid will be re-generated. default1 min0 max1 mrecrbf Global boundary face reconnection flag. [1] The specified BL thickness (if specified) is multiplied by cblsmax to determine the thickness of the BL grid region. [1] BL grid advancement is terminated locally when an element is rejected. [1] A cdfr value just above 1.0 will produce a grid with optimal element quality. [1] Quality improvement grid re-generation is performed on low-quality element regions. [1] Maximum number of true boundary surface allowed in a single low-quality region during quality improvement grid re-generation. [1] The maximum number of elements and nodes is increased and all arrays are reallocated if more elements or nodes are required to complete the grid. [1] Increasing cdfm above 0.0 will in general reduce the growth of element size from small to larger elements and increase the total number of grid nodes generated. [1]

If mchkvoli 0 then do not check element volumes of the input grid and attempt to correct those that are negative. [1] Check for and read any TAGS data file with the same case name as the input grid. [1] If found the grid BCs specified in the TAGS file will be used. [1] Equivalent to Program_Flag0 mqchk0 Output_Grid_File_Name_ _ No parameter value should be specified. -revbl Reverse BL normals for and open BL region grid with an open domain. [1]

Generate only an initial triangulation of the boundary points with a fully recovered boundary grid. [1] Additional nodes beyond those in the initial boundary grid may be required to complete boundary recovery and obtain an initial triangulation. default1.25 min1 max3 crbf Boundary recovery node placement factor. [1] An external routine may or may not use a background grid (if any) and/or source nodes (if any) that are input to AFLR. AFLR includes a built-in external sizing evaluation routine. [1] This option is set internally if a background grid is input and meval0. [1] Reset initial normal spacing and/or BL thickness values set in the input surface grid file with those determined from the command line arguments (such as -y+, -blds, -bldel, etc). [1] If mblreseti 1 then reset the initial normal spacing and/or BL thickness values set in the input arrays (or set by the input surface grid file) with those determined from the BL parameter values (such as blyp, dsdef, deldef, etc). [1]

BL normal spacing is increased multiple layers during generation and then subdivided after the entire BL grid is generated to obtain the true spacing. [1]

The background grid output files will be named case_name.back. [1] After the background grid is generated use it to generate the final volume grid. [1] Note that not all codes have debug mode implemented. default0 min0 max1 mbackgen Generate a background grid. [1] Instead generate the background grid separately with -backgen or mbackgen1. [1] If mbl 2 then generate a structured-layer (SL) grid next to all boundary faces with a grid boundary condition that is less than zero. [1] The distribution function multiplier #2, cdf2, is used exactly as the standard distribution function multiplier, cdf, on all boundary surface faces with a negative grid boundary condition. [1] A large number of faces indicates that there are issues with the boundary surface grid that can not be addressed with grid re-generation. [1]

If mw_func 1 then write grid function file with scalar isotropic length scale and/or directional length scale metric. [1] If only one grid BC flag is specified then it must be terminated with a comma. [1] This flag is only applicable in cases with a BL/SL/SNS grid (-bl, -bls, -sl, -sls, -sns, or -snsids flag). [1] This flag is only applicable in cases with a SNS grid (-sns or -snss flag). [1]

There are reasons to consider the mathematical foundation of the finite element approximation more sound, for instance, because the quality of the approximation between grid points is poor in FDM. [9] SL grid advancement is terminated locally when an element is rejected. [1]

The surface grid will be fixed and assumed to intersect the BL/SL/SNS for all fixed intersecting surfaces adjacent to a BL/SL/SNS surface. [1] A low quality face has a ratio near 0. where Rc Circumscribed Radius Ri Inscribed Radius Area Face Area Lmax Maximum Face Edge Length C22 0.384900 C32 3.464102 This is a UG_GQ LIB parameter. default0 min0 max15 GQ_Surf_Output_Flag Surface grid quality output flag. [1] A low quality element has a ratio near 0. where Rc Circumscribed Radius Ri Inscribed Radius Vol Element Volume Lmax Maximum Element Edge Length C21 1.948557 C31 4.898979 This is a UG_GQ LIB parameter. default1 min0 max15 GQ_Vol_Output_Flag Volume grid quality output flag. [1]

No grid generation is performed. default0 min0 max1 mblchkv BL element volume checking flag. [1] If mw_bc_surf 0 then do not write boundary surface grid file after setting boundary conditions If mw_bc_surf 1 then write boundary surface grid file after setting boundary conditions. default0 min0 max1 mw_bl_func BL level function file flag. [1] If it is not set in the input grid file, then all boundary faces are set to a negative grid boundary condition value unless set otherwise using the -sls or equivalent flag. [1] Equivalent to GQ_Vol_Measure_Flag15 No parameter value should be specified. -qchk Read input grid file and generate element quality measure information. [1] Equivalent to GQ_Surf_Measure_Flag0 No parameter value should be specified. -qstat Read input grid file and generate quality statistics. [1]

Equivalent to GQ_Vol_Measure_Flag0 No parameter value should be specified. -qsall Generate surface grid quality data for all quality measures. [1]

In boundary-layer (BL) generation mode it also uses the Advancing-Normal Boundary-Layer (ANBL) procedure to generate a tetrahedral, pentahedral, and/or hexahedral BL mesh adjacent to BL generating surfaces. [1] If m_ice 1 then generate an interior core mesh. default0 min0 max2 mblend BL termination flag. [1] If the initial mesh is a volume mesh then the distribution function multiplier, cdf, is replaced with the volume mesh value, cdf_vol. Not applicable if the initial mesh is a boundary surface mesh. default1 min0.1 max1e+06 cdffblm1 Maximum BL edge length factor #1. [1] Typical maximum angle for a usable volume mesh. default179.9 min0 max180 angbfmax Boundary surface face quality threshold. [1] Typical minimum quality function q for a usable volume mesh. default0.01 min0 max1 vol_tol Relative tolerance for element volume checking. [1]

The distribution function multiplier (controls length scale) for fully unstructured mesh elements in the gap between interior core boundary nodes and existing boundary nodes is set equal to the minimum of cdf and cdf_gap_ic. [1] Equivalent to Help_UG_IO_Flag2 No parameter value should be specified. -ice Generate an interior core mesh with varying element size. [1] Equivalent to m_ice1 No parameter value should be specified. -ice1 Generate an interior core mesh with uniform element size. [1]

AFLR2/AFLR3 parameter. default1 min1 max2 mw_ice ICE output debug mesh file flag. [1] If mw_ice 2 then output ICE intermediate debug mesh files as with mw_ice1 and also during quad flag generation at each refinement level. [1]

The input mesh file contains the coordinates and connectivity for a fully connected surface triangulation. [1] These files contain the ICE surface mesh data that defines the gap regions. [1] Treating problems with discontinuities with XFEMs suppresses the need to mesh and remesh the discontinuity surfaces, thus alleviating the computational costs and projection errors associated with conventional finite element methods, at the cost of restricting the discontinuities to mesh edges. [9] A discretization strategy is understood to mean a clearly defined set of procedures that cover (a) the creation of finite element meshes, (b) the definition of basis function on reference elements (also called shape functions) and (c) the mapping of reference elements onto the elements of the mesh. [9] Although the approaches used by these pioneers are different, they share one essential characteristic: mesh discretization of a continuous domain into a set of discrete sub-domains, usually called elements. [9] Option Parameters (Rank 1 – Often Used) ________________________________________________________________________________ m_ice Interior core (ICE) mesh flag. [1]

Option Parameters (Rank 3 – Seldom Used) ________________________________________________________________________________ BC_IDs List of IDs to reset grid BC parameters. [1] AFLR2/AFLR3 parameter. default2 min1 max10 nqrgadd Minimum additional grid re-generation nodes. [1] Do not convert source type transparent boundary faces with a grid BC of 3 to source nodes. [1] If msource 1 and sources are input then insert the sources into the initial grid. [1] If meval -1 then use interpolation from an input background grid for sizing evaluation. [1] Use external sizing routine with or without a background grid. [1]

The initial re-generation distribution function multiplier cdfqrg is reduced iteratively by the factor dcdfqrg during quality improvement grid re-generation if quality does not improve. [1] The minimum re-generation distribution function multiplier cdfqrgmin is used to limit the minimum distribution function multiplier during quality improvement grid re-generation. [1] During quality improvement grid re-generation the distribution function multiplier cdfqrg is iteratively reduced. [1]

;If mopen 1 then generate an open BL region grid for a closed domain. [1] This option can be useful if the physical BL region is very thick and the grid BL region is not as thick. [1] An open BL region grid can be generated in an open or closed domain with this option. [1]

Increasing cdf will increase the total number of grid nodes generated. [1] Decreasing cdf will decrease the total number of grid nodes generated. [1]

If the vector BL_IDs is set to 2,5,6 then there are 3 entries in the vector and all faces with surface IDs 2, 5 or 6 will have BL grid generation and all others will not. [1] For example using “-bls 12,1,10” would turn on BL grid generation from the boundary faces with surface IDs 12, 1 and 10 and turn off BL grid generation from all other boundary faces. [1]

If mw_blds_func 1 then write BL spacing and normal vector file and a corresponding surface grid file. [1] If mw_bl_func 1 then write BL level function file and a corresponding surface grid file. [1]

Option Parameters (Rank 2 – Sometimes Used) ________________________________________________________________________________ GQ_Surf_Measure_Flag -qs Surface grid quality measure flag. [1] If mfchkn 1 then check distance between candidate nodes and all existing nodes. default0 min0 max1 mimadd Initial grid generation element flag option. [1] Boundary faces with high aspect-ratio typically require transformation during the boundary recovery phase of initial grid generation. default1 min0 max1 mw_debug_grid Debug volume grid file flag. [1] The metric field may be set from an externally defined sizing function (meval!0) or the use of BL blending (mmetblbl1 or 2). default0 min0 max2 mopen Open BL region grid generation flag. [1]

In the preceding treatment, the grid consisted of triangles, but one can also use squares or curvilinear polygons. [9] The distribution function and metric from sources are weighted by csrcw and that from the local grid is weighted by 1-csrcw. [1] Note that if there is an existing background grid, it is ignored (as with -no_back). [1] Remove boundary face connectivity for standard transparent boundary faces with a grid BC of 5 from the final grid. [1] If any other boundary faces were specified to be fixed intersecting surfaces within the input grid file they will be reset to standard surfaces (a magnitude of one). [1] The volume grid will have the same case name as set for the output grid file except it will have a.## suffix before the format and file type suffixes (where ## will be the value of ngen input (or default value if not set). [1] This parameter is set by the main program to match the actual output grid file type and format specified. [1] With this option an output grid file type that supports prism, pyramid, and tet elements should be specified. [1] Equivalent to cdf20.7 No parameter value should be specified. -convert Read input grid file and write output grid file. [1] Equivalent to mopen2 No parameter value should be specified. -qall Generate volume grid quality data for all quality measures. [1] Equivalent to Program_Flag0 mqchk2 Output_Grid_File_Name_ _ No parameter value should be specified. -qnone Do not generate any volume grid quality data. [1]

This is a UG_GQ LIB parameter. default1 min0 max1 GQ_Vol_Measure_Flag -q Volume grid quality measure flag. [1] GQ_Surf_Measure_Flag : Surface grid quality measure flag. -qs : Surface grid quality measure flag. [8]

BL surface face reconnection is limited if the maximum difference between the number of BL levels for the BL nodes on the face is greater than nblrbf. [1] This option attempts to smooth out differences in BL layer normal spacing between the fixed faces and nearby region over nblsmthlisf layers of adjacent boundary surface faces. [1]

Only applicable if the BL/SL/SNS flag is on (mbl!0). default10000 min0 max10000000 nbldiff Maximum difference in BL levels. [1] Only applicable if the BL/SL/SNS flag is on (mbl!0). default3 min2 max100 nblrbf BL level difference reconnection limit. [1]

BL/SL/SNS grid generation is terminated locally if the edge length between active BL nodes grows to a value that is greater than cdffblm2 multiplied by the corresponding edge length on the initial boundary surface. [1] With BL grid generation the grid is written to a file by routines that use temporary files to minimize memory requirements instead of standard UG_IO routines. [1]

If the planar angle for a vertex of any face is greater than angqbfm then the triangulation is considered low-quality and mrec4 is set to a value of 1 (turns on reconnection of 4-4 element combinations during grid generation). [1] This flag overrides any grid boundary condition set from the input grid file. [1] The input grid file contains the coordinates and connectivity for a fully connected surface triangulation. [8] If BG_Case_Name is not specified then the case name from the input grid file is used. [1] BG_Case_Name : Case name for background grid and function file name -ib -iback -bcase : Case name for background grid and function file name Input_Grid_File_Name : Case name or input grid file name. -i -igrid -case : Case name or input grid file name. [8] This is a program parameter. default Input_Grid_File_Name -i -igrid -case Case name or input grid file name. [1] This is a program parameter. default Output_Grid_File_Name -o -ogrid Output grid file name or suffix. [1]

Normally all source-type transparent/ embedded boundary faces with a BC flag of 3 are converted to source nodes, all standard transparent/embedded boundary faces with a BC flag of 5 are included in the output grid as boundary faces, and all internal-type transparent/embedded boundary faces with a BC flag of 6 are included in the grid throughout grid generation and then the boundary face connectivity (not the coordinates) is removed from the output grid. [1] For example using “-sls 12,1,10” would turn on SL grid generation from the boundary faces with surface IDs 12, 1 and 10 and turn off SL grid generation from all other boundary faces. [1] During grid generation large elements that have all edges larger than the distribution function (local node spacing) are subdivided using centroid node placement. [1] Maximum number of element subdivisions for direct node insertion during field grid generation. default100 min1 max10000000 nlsrgen Maximum number of LSRatio passes. [1] BL/SL/SNS grid generation is terminated locally if the edge length between an active and inactive BL node is greater than cdffblm1 multiplied by the maximum of the local normal spacing and the edge length between the same nodes at the last level that they were active. [1]

The BL boundary surface grid file contains the inflated BL surfaces along with all other non-BL surfaces. [1] The BL boundary surface grid file will be named case_name.BL.surf. [1] If mw_bl_surf 0 then do not write BL boundary surface grid file. [1] The BLISF boundary surface grid file contains the complete boundary surface grid with unique surface IDs for boundary surface faces that are of the same BL level on a BLISF boundary surface (a surface that is fixed and intersects the BL region. [1]

Boundary faces with high aspect-ratio typically require transformation (mtrb1) or an alternative metric approach (mmetb1) during the boundary recovery phase of initial grid generation. default0 min0 max1 mpfrmt Memory reduction output grid file format. [1] Used to determine tolerance used during deletion of construction elements and sub-grid generation phases of initial grid generation. default0.5 min0.4 max0.94 ctolm Initial grid volume tolerance exponent. default0.88 min0.5 max0.94 dangqrgen Re-generation element angle tolerance. [1] After background grid generation is complete it is used to generate the final volume grid. [1]

In either case the code will reallocate memory as needed during grid generation. default0 min0 max2000000000 meval External evaluation option flag. [1] This option typically results in a slightly improved grid quality at the expense of an increase in required CPU time. default2 min1 max3 mrecqm Quality local-reconnection flag. [1] GQ_Vol_Measure_Flag : Volume grid quality measure flag. -q : Volume grid quality measure flag. [8]

If GQ_Surf_Output_Flag 0 then do not create grid quality output file(s). [1]

If mw_ice_surf 0 then do not output ICE boundary surface mesh files. [1] If mw_ice 0 then do not output ICE intermediate mesh files. [1]

If nref_max 1 then use one level and set the length scale equal to an average value from the background mesh. [1] One hopes that as the underlying triangular mesh becomes finer and finer, the solution of the discrete problem (3) will in some sense converge to the solution of the original boundary value problem P2. [9] Delaunay circumsphere tolerance reduction factor for boundary node insertion. default0.01 min1e-06 max0.1 cgtol Mesh merge glue tolerance factor. default10 min1 max1e+12 cmv1 Initial node movement tolerance. [1]

It includes the use of mesh generation techniques for dividing a complex problem into small elements, as well as the use of software program coded with FEM algorithm. [9] If this condition is not satisfied, we obtain a nonconforming element method, an example of which is the space of piecewise linear functions over the mesh which are continuous at each edge midpoint. [9] The size of the interior core mesh elements vary between the length scales specified by df_ic_max and df_ic_min unless they are equal to zero. [1] More advanced implementations (adaptive finite element methods) utilize a method to assess the quality of the results (based on error estimation theory) and modify the mesh during the solution aiming to achieve approximate solution within some bounds from the ‘exact’ solution of the continuum problem. [9] With this option an interior core mesh is generated with varying element size. [1]

General Parameters (Rank 1 – Often Used) ________________________________________________________________________________ -bcheck Check boundary surface mesh. [1] If mbcheck 1 then only check the input boundary surface mesh and then return. [1]

The values will be those that exist at the end of mesh generation. [1] If the main method for increasing precision is to subdivide the mesh, one has an h -method ( h is customarily the diameter of the largest element in the mesh.) [9] Typical minimum volume ratio for a usable volume mesh. default0.01 min0 max1 vx Flow X-direction vector component. [1] If nref_max 0 then determine the appropriate number of levels from the background mesh. [1] If they are equal to zero then the length scale is determined from the background mesh. [1]

FEM mesh created by an analyst prior to finding a solution to a magnetic problem using FEM software. [9] These examples of mesh are from the Cambridge English Corpus and from sources on the web. [10]

If msource 2 and meval 0 (on input) or meval -2 (after reset) and sources are input then create an oct-tree of the source nodes for interpolating the local distribution function and metric during grid generation. [1] The BL grid generation is usually followed by an isotropic grid generation phase to fully discretize the domain. [1]

If a background grid file and a background length-scale function file are found then they are read for use in the external sizing evaluation routine. [1] A grid and length-scale function file with naming “case_name.back.format_and_type” are considered background grid files. [1]

If mw_debug_grid 0 then do not write debug volume grid file before quality post processing. [1] Specifies either the case name or full file name for the input grid file. [1] If mw_blisf_surf 0 then do not write BLISF boundary surface grid file. [1] The boundary surface grid file will be named case_name.BLISF.surf. [1]

If Output_Grid_FileNULL then do not write an output grid file. [1]

If mrec4 1 then reconnect 4-4 element combinations during grid generation. [1] Same as angrbfsd except that it is used only during secondary grid generation in cases with BL regions. [1]

The error estimates are computed as the maximum norm of the difference of two solutions computed on different meshes. [10]

This generates a 3D grid of interpolated Light Probes inside a bounding volume A closed shape representing the edges and faces of a collider or trigger. [11] Creating TINs from rasters isn’t straightforward, since there are many different triangulations that approximate a grid with the same error, but using different vertex sets. [2]

Following the example in scikit-image doc I generate a spherical surface mesh with marching cubes algorithm. [5] Tin-Terrain is a simple command line tool that will generate a mesh from DEM files either as TIN or TRN. [2]

An inferior mesh quality may leave out certain important phenomenon such as the boundary layer that occurs in fluid flow. [12] Therefore generally a novice CAE user makes mistake in defining quality mesh based on few parameters. [12] I think above set of rules set up good ground rules for mesh quality for numerical simulation. [12] Set options so that adaptmesh refines the triangles using the worst error criterion until it obtains a mesh with at least 500 triangles. [13]

The three components of the algorithm are the error indicator function (which computes an estimate of the element error contribution), the mesh refiner (which selects and subdivides elements), and the termination criteria. [13] Finite element methods and computational fluid dynamics applications place constraints on both the shapes and sizes of the mesh elements. [12]

I have asc DTM file that I need to convert to a ply mesh file. [2] Are there any tools that can take a DTM, in asc or geotiff format and generate a mesh from this that can used in meshlab or similar software. [2] If no initial mesh is provided, the result of a call to initmesh with no options is used as the initial mesh. [13] The first triangular mesh generation is provided as an optional argument to adaptmesh or obtained by a call to initmesh without options. [13] He has done major contribution in conceptualizing, designing, and developing 3D CAD application, faceted geometry kernel, faceted Boolean, mesh generation software with automatic fluid volume extraction for dirty CAD and Point cloud meshing. [12]

Mesh quality is very much dependent on the purpose (numerical simulation) for which one want to use it. [12] There are several reasons because of which numerical solver insist use of good quality mesh. [12] A Mesh can receive light from the Light Probe system and reflections from the Reflection Probe system depending on the settings of the Use Light Probes and Use Reflection Probes options. [11] A DTM raster can be represented by triangle meshes by finding a set of non-overlapping triangles that covers the entire mesh and approximates the elevation field. [2] It may be useful to set the anchor in cases where a GameObject contains two adjoining Meshes; since each Mesh has a separate bounding box, the two are lit discontinuously at the join by default. [11]

CPU time is a necessary yet an undesirable factor : For a highly refined mesh, where the number of cells per unit area is maximum the CPU time required will be relatively large. [12] One thing is sure one cannot generalize a good mesh purely based on geometric parameter. [12] The Mesh Renderer GameObject Component as displayed in the Inspector A Unity window that displays information about the currently selected GameObject, Asset or Project Settings, alowing you to inspect and edit the values. [11] The greater the rate of convergence, the better is the mesh quality : It means that the correct solution has been achieved faster. [12] It’s a superior quality mesh with 3.75 squares per inch in a natural, but sturdy cotton. [14] A better mesh quality guarantees a more accurate solution : For improving the mesh quality for accurate solution, one may need to refine the mesh at certain areas of the geometry where the gradient of the field whose solution is sought is high. [12] For the solution of given accuracy and rate of convergence, greater CPU time required indicates an inferior mesh quality. [12]

Partial Differential Equation Toolbox™ provides the refinemesh function for global, uniform mesh refinement for 2-D geometries. [13] adaptmesh(g,b,c,a,f) and adaptmesh(g,b,c,a,f,’PropertyName’,PropertyValue) perform adaptive mesh generation and PDE solution for elliptic problems with 2-D geometry. [13] The MesherVersion property chooses the algorithm for mesh generation. [13]

For Navier stokes (NS) simulation you need a dense mesh near the wing tip and in the wake region. [12] Here’s a Python script that uses the GDAL library to read a raster DTM, and then writes out a binary PLY mesh. [2] If the PDE is scalar, meaning that is has only one equation, then u is a column vector representing the solution u at each node in the mesh. [13] You can provide an initial mesh, or let adaptmesh call initmesh automatically. [13] All the Materials used by a Mesh Renderer are held in the Materials list. [11] This triangular mesh is used as starting mesh for the adaptive algorithm. [13] Following image shows mesh used for FEA and CFD simulation of a wing. [12] Following simple rules are generally used by CAE engineers to quantify good mesh. [12]

Refinement is also stopped when the number of triangles in the mesh exceeds Maxt. [13] This type of mesh configuration is also known as O topology mesh. [12]

The larger the value of this parameter, the smaller that LAMMPS will set the grid size, to achieve the requested accuracy. [4] If minorder is set to the same value as order then no reduction is allowed, and LAMMPS will generate an error if the grid communication is non-nearest-neighbor and overlap is set to no. [4]

Without this setting, LAMMPS chooses the parameter automatically as a function of cutoff, precision, grid spacing, etc. This means it can vary from one simulation to the next which may not be desirable for matching a KSpace solver to a pre-tabulated pairwise potential. [4] This setting can also be useful if Ewald or PPPM fails to choose a good grid spacing and G-ewald parameter automatically. [4]

Note that there is an inherent trade-off involved: a small grid will lower the cost of FFTs or MSM direct sum, but a larger order parameter will increase the cost of interpolating charge/fields to/from the grid. [4] When this option is not set, the PPPM or MSM solver chooses its own grid size, consistent with the user-specified accuracy and pairwise cutoff. [4] In the Grid Line Properties section, set the Parallel axis to the Y Axis 1. [15] The mesh/disp keyword sets the grid size for kspace style pppm/disp. [4] If it set to no and overlap occurs, then LAMMPS will reduce the order setting, one step at a time, until the ghost grid overlap only extends to nearest neighbor processors. [4]

This communication is distinct from the communication inherent in the parallel FFTs themselves, and is required because processors interpolate charge and field values using grid point values owned by neighboring processors (i.e. ghost point communication). [4] The overlap keyword can be used in conjunction with the minorder keyword with the PPPM styles to adjust the amount of communication that occurs when values on the FFT grid are exchanged between processors. [4] The smaller the order value, the larger the grid size will be. [4]

It then performs analytic differentiation on the single quantity to generate the 3 components of the electric field at each grid point. [4] The accuracy setting is used in conjunction with the pairwise cutoff to determine the number of K-space vectors for style ewald, the FFT grid size for style pppm, or the real space grid size for style msm. [4] The order keyword determines how many grid spacings an atom?s charge extends when it is mapped to the grid in kspace style pppm or msm. [4] The order/disp keyword determines how many grid spacings an atom?s dispersion term extends when it is mapped to the grid in kspace style pppm/disp. [4]

If you want grid lines at the minor tick marks, check the box next to the Minor tick grid line option. [15]

Here is an example of loading a mesh from file and colorizing its faces. [16] A mesh is imported into Onshape Part Studio, and shown in the Parts lists under Meshes (below Surfaces). [17] Onshape enables you to import three faceted file formats:STL, OBJ and Parasolid Mesh for visualization and referencing. [17] Check out the cross section example or possibly the integration of a function over a mesh example. [16] We stock this versatile, easily adaptable product in various opening and mesh sizes, thicknesses, and primary materials to satisfy a wide range of uses and custom design ideas. [18] The option defaults are mesh mesh/disp 0 0 0, order order/disp 5 (PPPM), order 10 (MSM), minorder 2, overlap yes, force -1.0, gewald gewald/disp 0.0, slab 1.0, compute yes, cutoff/adjust yes (MSM), pressure/scalar yes (MSM), fftbench no (PPPM), diff ik (PPPM), mix/disp pair, force/disp/real -1.0, force/disp/kspace -1.0, split 0, tol 1.0e-6, and disp/auto no. [4] The diff keyword specifies the differentiation scheme used by the PPPM method to compute forces on particles given electrostatic potentials on the PPPM mesh. [4] Mesh points are able to be used as vertices for creating planes. [17]

The PPPM order parameter may be reset by LAMMPS when it sets up the FFT grid if the implied grid stencil extends beyond the grid cells owned by neighboring processors. [4] The default for this parameter is 5 for PPPM and 8 for MSM, which means each charge spans 5 or 8 grid cells in each dimension, respectively. [4]

RANKED SELECTED SOURCES(18 source documents arranged by frequency of occurrence in the above report)

1. (204) AFLR3 Option Details

2. (21) kspace_modify command — LAMMPS documentation

3. (16) LearnCAx | Good Looking Mesh May Not Always be Good for the Simulation

4. (11) Adaptive 2-D mesh generation and PDE solution – MATLAB adaptmesh

5. (11) Finite element method – Wikipedia

6. (8) convert – Seeking tool to generate Mesh from DTM? – Geographic Information Systems Stack Exchange

7. (7) AFLR3 Overview

8. (5) Unity – Manual: Mesh Renderer

9. (3) Mesh

10. (2) mesh Definition in the Cambridge English Dictionary

11. (2) How can I add grid lines to my graph in Grapher? – Golden Software Support

12. (2) trimesh PyPI

13. (2) python – How to set the origin for the mesh with mplot3d? – Stack Overflow

14. (1) Latch Hook & Locker Hook Rug Canvas – 3.75 Mesh With Grid – Color Crazy

15. (1) Square – Wire Mesh | McNICHOLS

16. (1) Which is the best meshing software for CFD? I am aware of the Ansys Meshing but I came to know that HyperMesh is far better in meshing. – Quora

17. (1) Finite element methods on composite meshes for tuning plasma equilibria in tokamaks | SpringerLink

18. (1) 2D Hydraulic Modeling – xpswmm/xpstorm Resource Center – Innovyze Resource Center